CVE-2025-39946

MEDIUMNVD 5.55.5
EchelonGraph scoreMEDIUM confidence

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

Score 5.5 from GitHub Security Advisory published 2025-10-04. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Elevated

Also known asEUVD-2025-32393 (ENISA EUVD) · GHSA-cgf5-f6fj-4v5q (GitHub Security Advisories)Source: ENISA EUVD

5.5EG
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: 10%CVSS: 5.5Exploit: Public PoCExposed services: Not assessed

A fix is available — apply it.

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

tls: make sure to abort the stream if headers are bogus

Normally we wait for the socket to buffer up the whole record before we service it. If the socket has a tiny buffer, however, we read out the data sooner, to prevent connection stalls. Make sure that we abort the connection when we find out late that the record is actually invalid. Retrying the parsing is fine in itself but since we copy some more data each time before we parse we can overflow the allocated skb space.

Constructing a scenario in which we're under pressure without enough data in the socket to parse the length upfront is quite hard. syzbot figured out a way to do this by serving us the header in small OOB sends, and then filling in the recvbuf with a large normal send.

Make sure that tls_rx_msg_size() aborts strp, if we reach an invalid record there's really no way to recover.

CVSS v3
5.5
EG Score
5.5MEDIUMmedium confidence
EG Risk
56
EG Risk 56/100

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)
Severity55% × 45%
Impact severity (EG Severity): CVSS 5.5 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.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (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
10%
EPSS %ILE
95th
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 (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.

EG Severity
5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
10% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). 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 or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days 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 or medium mission impact; Attend at high (mission-essential systems).

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

Exploitation none (CISA Vulnrichment) · Automatable yes (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)3 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

October 4, 2025

Last Modified

October 19, 2026

Advisory Details (5)

Auto-updated Oct 16, 2026
Patch available.
Web page

tls: make sure to abort the stream if headers are bogus - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0aeb54ac4cd5cf8f60131b4d9ec0b6dc9c27b20d
Web page

tls: make sure to abort the stream if headers are bogus - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/208640e6225cc929a05adbf79d1df558add3e231
Web page

tls: make sure to abort the stream if headers are bogus - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4cefe5be73886f383639fe0850bb72d5b568a7b9
Web page

tls: make sure to abort the stream if headers are bogus - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b36462146d86b1f22e594fe4dae611dffacfb203
Web page

tls: make sure to abort the stream if headers are bogus - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/61ca2da5fb8f433ce8bbd1657c84a86272133e6b

Vendor Advisories for CVE-2025-39946(2)

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

Patch Availability(22)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulinux-tools-azure-6.14 (6.14.0-1017.17) @ plucky2026-10-19ubuntu
ubuntulinux-tools-oem-6.14 (6.14.0-1017.17) @ noble2026-10-19ubuntu
ubuntulinux-virtual-6.8 (6.8.0-100.100) @ noble2026-10-19ubuntu
ubuntulinux-tools-realtime-hwe-22.04 (6.8.1-1041.42~22.04.1) @ jammy2026-10-19ubuntu
ubuntulinux-tools-gcp-edge (6.8.0-1047.50~22.04.2) @ jammy2026-10-19ubuntu
ubuntulinux-tools-realtime-6.8.1 (6.8.1-1041.42) @ noble2026-10-19ubuntu
ubuntulinux-tools-fips-6.8 (6.8.0-100.100+fips1) @ noble2026-10-19ubuntu
ubuntulinux-tools-oracle-lts-24.04 (6.8.0-1043.44) @ noble2026-10-19ubuntu
ubuntulinux-virtual-hwe-22.04-edge (6.8.0-100.100~22.04.1) @ jammy2026-10-19ubuntu
ubuntulinux-tools-gke-64k-6.8 (6.8.0-1043.48) @ noble2026-10-19ubuntu
ubuntulinux-tools-azure-edge (6.8.0-1051.57~22.04.1) @ jammy2026-10-19ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1046.52) @ noble2026-10-19ubuntu
ubuntulinux-tools-ibm-lts-24.04 (6.8.0-1044.44) @ noble2026-10-19ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1046.52+fips1) @ noble2026-10-19ubuntu
ubuntulinux-tools-realtime-hwe-24.04 (6.14.0-1017.17~24.04.1) @ noble2026-10-19ubuntu
ubuntulinux-tools-gcp-fips-6.8 (6.8.0-1047.50+fips1) @ noble2026-10-19ubuntu
ubuntulinux-tools-lowlatency-hwe-20.04-edge (6.8.0-100.100.1) @ noble2026-10-19ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1046.49.1) @ noble2026-10-19ubuntu
ubuntulinux-virtual-hwe-24.04-edge (6.14.0-37.37) @ plucky2026-10-19ubuntu
ubuntulinux-xilinx-zynqmp (6.8.0.1023.24) @ noble2026-10-19ubuntu
redhatkernel-0:6.12.0-124.11.1.el10_12025-11-17redhat
linuxKernel @ 6.1.154 (fixes >=6.0.0)—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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
linux-6.16.1.106-3~deb11u1 ... 6.1.153-1~deb11u1 (12 versions)
  • every version up to 6.1.158-1~deb11u1: fixed in 6.1.158-1~deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 6.1.99-1 (44 versions)
  • every version up to 6.1.158-1: fixed in 6.1.158-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.38-1 ... 6.12.57-1~bpo12+1 (6 versions)
  • every version up to 6.12.57-1: fixed in 6.12.57-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.16~rc7-1~exp1 (67 versions)
  • every version up to 6.16.9-1: fixed in 6.16.9-1
—

Additional Vendor Advisories

(20)

Data Freshness Timeline

(refreshed 7× in last 7d / 56× 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 98 of 234 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. 2 repeat rows among the latest 100 are merged into the row they repeat. The 136 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 10% · 95th percentile
  2. 2026-10-31 16:31 UTCEPSS rescoreEPSS 10% · 95th percentile
  3. 2026-10-30 16:32 UTCEPSS rescoreEPSS 10% · 95th percentile
  4. 2026-10-29 16:31 UTCEPSS rescoreEPSS 10% · 95th percentile
  5. 2026-10-28 16:30 UTCEPSS rescoreEPSS 10% · 95th percentile
  6. 2026-10-28 13:25 UTCOSV refresh
  7. 2026-10-27 16:30 UTCEPSS rescoreEPSS 10% · 95th percentile
  8. 2026-10-25 16:31 UTCEPSS rescoreEPSS 10% · 95th percentile
  9. 2026-10-25 16:28 UTCEG score recompute
  10. 2026-10-24 16:31 UTCEPSS rescoreEPSS 10% · 95th percentile
  11. 2026-10-23 16:30 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  12. 2026-10-22 16:33 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  13. 2026-10-21 16:31 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  14. 2026-10-20 16:31 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  15. 2026-10-19 21:26 UTCEG score recompute▼ 4.30
  16. 2026-10-19 21:26 UTCVendor advisory
  17. 2026-10-19 21:26 UTCGHSA enrichmentGHSA-cgf5-f6fj-4v5q · GitHub CVSS 5.5
  18. 2026-10-19 21:25 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  19. 2026-10-19 16:30 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  20. 2026-10-19 02:40 UTCEG score recompute
  21. 2026-10-19 02:40 UTCVendor advisory
  22. 2026-10-19 02:40 UTCGHSA enrichmentGHSA-cgf5-f6fj-4v5q · GitHub CVSS 5.5
  23. 2026-10-18 05:35 UTCEG score recompute
  24. 2026-10-18 01:01 UTCEG score recompute
  25. 2026-10-18 01:01 UTCVendor advisory
Show 73 more
  1. 2026-10-18 01:01 UTCGHSA enrichmentGHSA-cgf5-f6fj-4v5q · GitHub CVSS 5.5
  2. 2026-10-17 16:33 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  3. 2026-10-16 23:20 UTCEG score recompute
  4. 2026-10-16 23:20 UTCVendor advisory
  5. 2026-10-16 23:20 UTCGHSA enrichmentGHSA-cgf5-f6fj-4v5q · GitHub CVSS 5.5
  6. 2026-10-16 16:38 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  7. 2026-10-15 20:39 UTCEG score recompute
  8. 2026-10-15 20:39 UTCVendor advisory
  9. 2026-10-15 20:39 UTCGHSA enrichmentGHSA-cgf5-f6fj-4v5q · GitHub CVSS 5.5
  10. 2026-10-15 16:30 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  11. 2026-10-14 16:31 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  12. 2026-10-14 14:43 UTCEG score recompute
  13. 2026-10-14 14:43 UTCVendor advisory
  14. 2026-10-14 14:43 UTCGHSA enrichmentGHSA-cgf5-f6fj-4v5q · GitHub CVSS 5.5
  15. 2026-10-13 16:32 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  16. 2026-10-13 13:03 UTCVendor advisory
  17. 2026-10-13 13:02 UTCGHSA enrichmentGHSA-cgf5-f6fj-4v5q · GitHub CVSS 5.5
  18. 2026-10-12 17:06 UTCEG score recompute
  19. 2026-10-12 16:33 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  20. 2026-10-12 11:22 UTCVendor advisory
  21. 2026-10-12 11:22 UTCGHSA enrichmentGHSA-cgf5-f6fj-4v5q · GitHub CVSS 5.5
  22. 2026-10-11 20:39 UTCEG score recompute
  23. 2026-10-11 18:50 UTCEG score recompute
  24. 2026-10-11 15:27 UTCEG score recompute
  25. 2026-10-11 13:47 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  26. 2026-10-10 19:59 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  27. 2026-10-09 20:06 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  28. 2026-10-08 17:09 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  29. 2026-10-07 23:46 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  30. 2026-10-06 15:16 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  31. 2026-10-05 17:42 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  32. 2026-10-03 14:24 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  33. 2026-10-01 19:49 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  34. 2026-09-30 15:02 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  35. 2026-09-28 13:50 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  36. 2026-09-27 02:12 UTCOSV refresh
  37. 2026-09-26 15:58 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  38. 2026-09-26 00:24 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  39. 2026-09-24 14:02 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  40. 2026-09-23 13:47 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  41. 2026-09-18 19:27 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  42. 2026-09-17 19:29 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  43. 2026-09-16 14:07 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  44. 2026-09-16 05:14 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  45. 2026-09-12 15:00 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  46. 2026-09-11 14:52 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  47. 2026-09-11 09:35 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  48. 2026-09-10 09:33 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  49. 2026-09-08 21:59 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  50. 2026-09-07 16:00 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  51. 2026-09-07 11:18 UTCOSV refresh
  52. 2026-09-06 13:46 UTCEPSS rescoreEPSS 9.6% · 95th percentile
  53. 2026-09-04 05:05 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  54. 2026-09-02 14:11 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  55. 2026-09-01 13:53 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  56. 2026-09-01 04:38 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  57. 2026-08-30 19:16 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  58. 2026-08-30 01:21 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  59. 2026-08-28 21:40 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  60. 2026-08-27 14:24 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  61. 2026-08-26 14:45 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  62. 2026-08-25 13:48 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  63. 2026-08-23 00:18 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  64. 2026-08-21 23:48 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  65. 2026-08-20 22:54 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  66. 2026-08-20 20:31 UTCOSV refresh
  67. 2026-08-19 17:03 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  68. 2026-08-18 13:47 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  69. 2026-08-17 13:46 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  70. 2026-08-16 14:55 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  71. 2026-08-16 02:13 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  72. 2026-08-15 01:29 UTCEPSS rescoreEPSS 8.9% · 94th percentile
  73. 2026-08-13 21:59 UTCEPSS rescoreEPSS 8.9% · 94th percentile

Publicly available exploits

(1 reference)

Public exploit code is referenced for this CVE (1 GitHub PoC). Defenders should treat patch urgency accordingly.

  • GitHub PoCfarazsth98/exploit-CVE-2025-39946
    Published Oct 4, 2025

    Exploit for CVE-2025-39946, a bug in the Linux kernel's net/tls subsystem.

    Open source ↗

Frequently asked(5)

What is CVE-2025-39946?
CVE-2025-39946 is a medium-severity vulnerability; its CVE record was published on October 4, 2025. In the Linux kernel, the following vulnerability has been resolved: tls: make sure to abort the stream if headers are bogus Normally we wait for the socket to buffer up the whole record before we service it. If the socket has a tiny buffer, however, we read out the data sooner, to prevent…
When was the CVE record for CVE-2025-39946 published?
The CVE record for CVE-2025-39946 was published on October 4, 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 19, 2026; the record at its source may have been updated since.
Is CVE-2025-39946 actively exploited?
CVE-2025-39946 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 10% probability of exploitation in the next 30 days (95th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-39946?
CVE-2025-39946 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-39946?
A fix for CVE-2025-39946 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-39946 are linked in the Vendor Advisories panel on this page.

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