CVE-2025-21756

HIGHPre-NVD 7.87.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2025-02-27. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
Trending — 4 sources updated this weekElevated

Also known asEUVD-2025-5169 (ENISA EUVD) · GHSA-5828-2c94-235c (GitHub Security Advisories)Source: ENISA EUVD

7.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: 0.9%CVSS: 7.8Exploit: Public PoCExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

vsock: Keep the binding until socket destruction

Preserve sockets bindings; this includes both resulting from an explicit bind() and those implicitly bound through autobind during connect().

Prevents socket unbinding during a transport reassignment, which fixes a use-after-free:

  • vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)
  • transport->release() calls vsock_remove_bound() without checking if
sk was bound and moved to bound list (refcnt=1)
  • vsock_bind() assumes sk is in unbound list and before
__vsock_insert_bound(vsock_bound_sockets()) calls __vsock_remove_bound() which does: list_del_init(&vsk->bound_table); // nop sock_put(&vsk->sk); // refcnt=0

BUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730 Read of size 4 at addr ffff88816b46a74c by task a.out/2057 dump_stack_lvl+0x68/0x90 print_report+0x174/0x4f6 kasan_report+0xb9/0x190 __vsock_bind+0x62e/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Allocated by task 2057: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x85/0x90 kmem_cache_alloc_noprof+0x131/0x450 sk_prot_alloc+0x5b/0x220 sk_alloc+0x2c/0x870 __vsock_create.constprop.0+0x2e/0xb60 vsock_create+0xe4/0x420 __sock_create+0x241/0x650 __sys_socket+0xf2/0x1a0 __x64_sys_socket+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Freed by task 2057: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kmem_cache_free+0x1a1/0x590 __sk_destruct+0x388/0x5a0 __vsock_bind+0x5e1/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

refcount_t: addition on 0; use-after-free. WARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150 RIP: 0010:refcount_warn_saturate+0xce/0x150 __vsock_bind+0x66d/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

refcount_t: underflow; use-after-free. WARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150 RIP: 0010:refcount_warn_saturate+0xee/0x150 vsock_remove_bound+0x187/0x1e0 __vsock_release+0x383/0x4a0 vsock_release+0x90/0x120 __sock_release+0xa3/0x250 sock_close+0x14/0x20 __fput+0x359/0xa80 task_work_run+0x107/0x1d0 do_exit+0x847/0x2560 do_group_exit+0xb8/0x250 __x64_sys_exit_group+0x3a/0x50 x64_sys_call+0xfec/0x14f0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
51
EG Risk 51/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity78% × 45%
Impact severity (EG Severity): CVSS 7.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.9%
EPSS %ILE
59th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.

EG Severity
7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.9% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track* at medium mission impactTrack at low, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

February 27, 2025

Last Modified

October 15, 2026

Advisory Details (10)

Auto-updated May 12, 2026
Patch available.
Web pageMentions a patch (unverified)

[SECURITY] [DLA 4193-1] linux-6.1 security update

https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
Web pageMentions a patch (unverified)

[SECURITY] [DLA 4178-1] linux security update

https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
Web page

vsock: Keep the binding until socket destruction - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/fcdd2242c0231032fc84e1404315c245ae56322a
Web page

vsock: Keep the binding until socket destruction - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e7754d564579a5db9c5c9f74228df5d6dd6f1173
Web page

vsock: Keep the binding until socket destruction - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e48fcb403c2d0e574c19683f09399ab4cf67809c
Web page

vsock: Keep the binding until socket destruction - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b1afd40321f1c243cffbcf40ea7ca41aca87fa5e
Web page

vsock: Keep the binding until socket destruction - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/645ce25aa0e67895b11d89f27bb86c9d444c40f8
Web page

vsock: Keep the binding until socket destruction - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/42b33381e5e1f2b967dc4fb4221ddb9aaf10d197
Web page

vsock: Keep the binding until socket destruction - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3f43540166128951cc1be7ab1ce6b7f05c670d8b

Vendor Advisories for CVE-2025-21756(20)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(25)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulinux-tools-realtime (5.15.0.1082.86) @ jammy2026-10-28ubuntu
ubuntulinux-tools-gcp-fips (5.15.0.1081.71) @ jammy2026-10-28ubuntu
ubuntulinux-tools-intel-iotg-edge (5.15.0.1077.83~20.04.1) @ focal2026-10-28ubuntu
ubuntulinux-tools-azure-fips (5.15.0.1087.72) @ jammy2026-10-28ubuntu
ubuntulinux-xilinx-zynqmp-tools-host (5.15.0-1046.50) @ jammy2026-10-28ubuntu
ubuntulinux-tools-aws-edge (5.15.0.1082.89~20.04.1) @ focal2026-10-28ubuntu
ubuntulinux-tools-gcp-edge (5.15.0.1081.90~20.04.1) @ focal2026-10-28ubuntu
ubuntulinux-tools-oracle-edge (5.15.0.1079.85~20.04.1) @ focal2026-10-28ubuntu
ubuntulinux-tools-azure-nvidia (6.8.0-1014.15) @ noble2026-10-28ubuntu
redhatkpatch-patch2025-06-02redhat
redhatkernel-0:5.14.0-427.70.1.el9_42025-05-28redhat
redhatkernel-0:6.12.0-55.13.1.el10_02025-05-26redhat
redhatkernel-0:5.14.0-427.68.2.el9_42025-05-21redhat
redhatkernel-rt-0:4.18.0-553.53.1.rt7.394.el8_102025-05-21redhat
redhatkernel-0:4.18.0-553.53.1.el8_102025-05-21redhat
redhatkernel-rt-0:5.14.0-70.132.1.rt21.204.el9_02025-05-19redhat
redhatkernel-0:4.18.0-305.157.1.el8_42025-05-19redhat
redhatkernel-0:5.14.0-70.132.1.el9_02025-05-19redhat
redhatkernel-rt-0:4.18.0-305.157.1.rt7.234.el8_42025-05-19redhat
redhatkernel-0:5.14.0-570.17.1.el9_62025-05-19redhat
redhatkernel-0:4.18.0-372.145.1.el8_62025-05-15redhat
redhatkernel-0:5.14.0-284.117.1.el9_22025-05-15redhat
redhatkernel-rt-0:5.14.0-284.117.1.rt14.402.el9_22025-05-15redhat
redhatkernel-0:4.18.0-477.97.1.el8_82025-05-15redhat
linuxKernel @ 5.10.235 (fixes >=5.5.0)—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFix by version rangeDependents
linux5.10.103-1 ... 5.10.92-2 (45 versions)
  • every version up to 5.10.237-1: fixed in 5.10.237-1
—
linux-6.16.1.106-3~deb11u1 ... 6.1.129-1~deb11u1 (7 versions)
  • every version up to 6.1.137-1~deb11u1: fixed in 6.1.137-1~deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 6.1.99-1 (36 versions)
  • every version up to 6.1.133-1: fixed in 6.1.133-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 6.12.16-1: fixed in 6.12.16-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 6.12.16-1: fixed in 6.12.16-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(5)

Data Freshness Timeline

(refreshed 10× in last 7d / 48× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 96 of 242 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 4 repeat rows among the latest 100 are merged into the row they repeat. The 146 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:32 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  2. 2026-10-31 16:30 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  3. 2026-10-30 16:32 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  4. 2026-10-29 16:31 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  5. 2026-10-28 16:30 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  6. 2026-10-28 15:06 UTCEG score recompute
  7. 2026-10-28 15:06 UTCVendor advisory
  8. 2026-10-28 15:05 UTCGHSA enrichmentGHSA-5828-2c94-235c · GitHub severity HIGH · GitHub CVSS 7.8
  9. 2026-10-27 16:30 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  10. 2026-10-26 16:29 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  11. 2026-10-25 16:43 UTCEG score recompute
  12. 2026-10-25 16:31 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  13. 2026-10-24 16:30 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  14. 2026-10-23 16:30 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  15. 2026-10-22 16:32 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  16. 2026-10-21 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  17. 2026-10-21 16:11 UTCEG score recompute
  18. 2026-10-21 16:11 UTCVendor advisory
  19. 2026-10-21 16:11 UTCGHSA enrichmentGHSA-5828-2c94-235c · GitHub severity HIGH · GitHub CVSS 7.8
  20. 2026-10-20 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  21. 2026-10-19 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  22. 2026-10-18 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  23. 2026-10-18 05:46 UTCEG score recompute
  24. 2026-10-17 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  25. 2026-10-16 16:38 UTCEPSS rescoreEPSS 0.9% · 58th percentile
Show 71 more
  1. 2026-10-15 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  2. 2026-10-15 02:40 UTCEG score recompute
  3. 2026-10-15 02:40 UTCVendor advisory
  4. 2026-10-15 02:40 UTCGHSA enrichmentGHSA-5828-2c94-235c · GitHub severity HIGH · GitHub CVSS 7.8
  5. 2026-10-15 01:44 UTCEG score recompute
  6. 2026-10-15 01:44 UTCVendor advisory
  7. 2026-10-15 01:44 UTCGHSA enrichmentGHSA-5828-2c94-235c · GitHub severity HIGH · GitHub CVSS 7.8
  8. 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  9. 2026-10-13 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  10. 2026-10-12 17:19 UTCEG score recompute
  11. 2026-10-12 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  12. 2026-10-11 20:51 UTCEG score recompute
  13. 2026-10-11 19:01 UTCEG score recompute
  14. 2026-10-11 15:41 UTCEG score recompute
  15. 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  16. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  17. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  18. 2026-10-08 17:09 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  19. 2026-10-07 23:46 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  20. 2026-10-06 15:16 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  21. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  22. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  23. 2026-10-03 14:24 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  24. 2026-10-02 16:26 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  25. 2026-10-01 19:48 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  26. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  27. 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  28. 2026-09-27 03:45 UTCOSV refresh
  29. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  30. 2026-09-26 00:24 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  31. 2026-09-24 14:02 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  32. 2026-09-23 13:46 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  33. 2026-09-22 14:47 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  34. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  35. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  36. 2026-09-16 14:06 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  37. 2026-09-16 05:13 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  38. 2026-09-15 03:09 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  39. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  40. 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  41. 2026-09-11 14:51 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  42. 2026-09-11 09:35 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  43. 2026-09-10 09:33 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  44. 2026-09-08 21:59 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  45. 2026-09-07 16:00 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  46. 2026-09-07 12:48 UTCOSV refresh
  47. 2026-09-06 13:46 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  48. 2026-09-05 15:28 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  49. 2026-09-04 05:05 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  50. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  51. 2026-09-01 13:52 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  52. 2026-09-01 04:38 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  53. 2026-08-30 19:16 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  54. 2026-08-30 01:21 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  55. 2026-08-28 21:40 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  56. 2026-08-27 14:24 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  57. 2026-08-25 13:47 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  58. 2026-08-23 00:18 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  59. 2026-08-21 23:48 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  60. 2026-08-20 22:54 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  61. 2026-08-20 22:31 UTCOSV refresh
  62. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  63. 2026-08-18 13:47 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  64. 2026-08-17 13:46 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  65. 2026-08-16 14:55 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  66. 2026-08-16 02:13 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  67. 2026-08-15 01:29 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  68. 2026-08-13 21:59 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  69. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  70. 2026-08-10 23:59 UTCEPSS rescoreEPSS 0.9% · 55th percentile
  71. 2026-08-09 13:45 UTCEPSS rescoreEPSS 0.9% · 55th percentile

Publicly available exploits

(2 references)

Public exploit code is referenced for this CVE (2 GitHub PoCs). Defenders should treat patch urgency accordingly.

  • GitHub PoCkhoatran107/cve-2025-21756
    Published Jun 26, 2025
    Open source ↗
  • GitHub PoChoefler02/CVE-2025-21756
    Published Apr 18, 2025

    Exploit for CVE-2025-21756 for Linux kernel 6.6.75. My first linux kernel exploit!

    Open source ↗

Frequently asked(5)

What is CVE-2025-21756?
CVE-2025-21756 is a high-severity vulnerability; its CVE record was published on February 27, 2025. In the Linux kernel, the following vulnerability has been resolved: vsock: Keep the binding until socket destruction Preserve sockets bindings; this includes both resulting from an explicit bind() and those implicitly bound through autobind during connect(). Prevents socket unbinding during a…
When was the CVE record for CVE-2025-21756 published?
The CVE record for CVE-2025-21756 was published on February 27, 2025. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 15, 2026; the record at its source may have been updated since.
Is CVE-2025-21756 actively exploited?
CVE-2025-21756 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.9% probability of exploitation in the next 30 days (59th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-21756?
CVE-2025-21756 has a CVSS v3.1 base score of 7.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2025-21756?
A fix for CVE-2025-21756 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-21756 are linked in the Vendor Advisories panel on this page.

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Is Your Infrastructure Affected by CVE-2025-21756?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.