CVE-2025-39852

MEDIUMNVD 5.55.5
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-09-22. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

A fix is available — apply it.

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

net/tcp: Fix socket memory leak in TCP-AO failure handling for IPv6

When tcp_ao_copy_all_matching() fails in tcp_v6_syn_recv_sock() it just exits the function. This ends up causing a memory-leak:

unreferenced object 0xffff0000281a8200 (size 2496): comm "softirq", pid 0, jiffies 4295174684 hex dump (first 32 bytes): 7f 00 00 06 7f 00 00 06 00 00 00 00 cb a8 88 13 ................ 0a 00 03 61 00 00 00 00 00 00 00 00 00 00 00 00 ...a............ backtrace (crc 5ebdbe15): kmemleak_alloc+0x44/0xe0 kmem_cache_alloc_noprof+0x248/0x470 sk_prot_alloc+0x48/0x120 sk_clone_lock+0x38/0x3b0 inet_csk_clone_lock+0x34/0x150 tcp_create_openreq_child+0x3c/0x4a8 tcp_v6_syn_recv_sock+0x1c0/0x620 tcp_check_req+0x588/0x790 tcp_v6_rcv+0x5d0/0xc18 ip6_protocol_deliver_rcu+0x2d8/0x4c0 ip6_input_finish+0x74/0x148 ip6_input+0x50/0x118 ip6_sublist_rcv+0x2fc/0x3b0 ipv6_list_rcv+0x114/0x170 __netif_receive_skb_list_core+0x16c/0x200 netif_receive_skb_list_internal+0x1f0/0x2d0

This is because in tcp_v6_syn_recv_sock (and the IPv4 counterpart), when exiting upon error, inet_csk_prepare_forced_close() and tcp_done() need to be called. They make sure the newsk will end up being correctly free'd.

tcp_v4_syn_recv_sock() makes this very clear by having the put_and_exit label that takes care of things. So, this patch here makes sure tcp_v4_syn_recv_sock and tcp_v6_syn_recv_sock have similar error-handling and thus fixes the leak for TCP-AO.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

September 19, 2025

Last Modified

January 14, 2026

Patch Availability(11)

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.

Weakness Classification(1)

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

All Vendor Advisories

(10)

Data Freshness Timeline

(refreshed 9× in last 7d / 44× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-07-25 14:17 UTCEPSS rescore
  2. 2026-07-25 14:17 UTCEPSS rescore
  3. 2026-07-24 14:17 UTCEPSS rescore
  4. 2026-07-23 19:41 UTCOSV refresh
  5. 2026-07-23 02:55 UTCEG score recompute
  6. 2026-07-22 14:07 UTCEPSS rescore
  7. 2026-07-22 14:07 UTCEPSS rescore
  8. 2026-07-21 15:24 UTCEPSS rescore
  9. 2026-07-20 17:07 UTCEPSS rescore
  10. 2026-07-19 14:30 UTCEPSS rescore
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  12. 2026-07-19 02:28 UTCEPSS rescore
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  14. 2026-07-18 10:04 UTCEPSS rescore
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  16. 2026-07-16 17:02 UTCEPSS rescore
  17. 2026-07-15 16:57 UTCEPSS rescore
  18. 2026-07-15 16:57 UTCEPSS rescore
  19. 2026-07-15 01:59 UTCEPSS rescore
  20. 2026-07-15 01:59 UTCEPSS rescore
  21. 2026-07-13 22:29 UTCEPSS rescore
  22. 2026-07-13 22:29 UTCEPSS rescore
  23. 2026-07-13 06:12 UTCEPSS rescore
  24. 2026-07-11 08:27 UTCEPSS rescore
  25. 2026-07-11 08:27 UTCEPSS rescore
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  1. 2026-07-09 19:09 UTCEPSS rescore
  2. 2026-07-09 19:09 UTCEPSS rescore
  3. 2026-07-07 13:45 UTCEPSS rescore
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 14:01 UTCOSV refresh
  7. 2026-07-06 02:23 UTCEPSS rescore
  8. 2026-07-05 02:30 UTCEPSS rescore
  9. 2026-07-04 06:30 UTCEPSS rescore
  10. 2026-07-01 15:06 UTCEPSS rescore
  11. 2026-07-01 15:06 UTCEPSS rescore
  12. 2026-06-30 23:22 UTCEPSS rescore
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  14. 2026-06-29 14:06 UTCEPSS rescore
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  16. 2026-06-28 14:07 UTCEPSS rescore
  17. 2026-06-28 14:07 UTCEPSS rescore
  18. 2026-06-28 04:55 UTCEPSS rescore
  19. 2026-06-28 04:55 UTCEPSS rescore
  20. 2026-06-27 03:08 UTCEPSS rescore
  21. 2026-06-27 03:08 UTCEPSS rescore
  22. 2026-06-25 13:49 UTCEPSS rescore
  23. 2026-06-25 13:49 UTCEPSS rescore
  24. 2026-06-24 14:04 UTCEPSS rescore
  25. 2026-06-24 14:04 UTCEPSS rescore
  26. 2026-06-23 21:32 UTCEPSS rescore
  27. 2026-06-23 21:32 UTCEPSS rescore
  28. 2026-06-22 14:25 UTCEPSS rescore
  29. 2026-06-22 14:25 UTCEPSS rescore
  30. 2026-06-21 14:56 UTCEPSS rescore
  31. 2026-06-21 14:56 UTCEPSS rescore
  32. 2026-06-21 01:59 UTCEPSS rescore
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  34. 2026-06-19 19:25 UTCEPSS rescore
  35. 2026-06-19 19:25 UTCEPSS rescore
  36. 2026-06-18 17:52 UTCEPSS rescore
  37. 2026-06-18 17:52 UTCEPSS rescore
  38. 2026-06-18 02:05 UTCOSV refresh
  39. 2026-06-17 17:52 UTCEPSS rescore
  40. 2026-06-16 17:52 UTCEPSS rescore
  41. 2026-06-16 17:52 UTCEPSS rescore
  42. 2026-06-14 23:17 UTCEPSS rescore
  43. 2026-06-13 23:00 UTCEPSS rescore
  44. 2026-06-12 23:11 UTCEPSS rescore
  45. 2026-06-11 14:00 UTCEPSS rescore
  46. 2026-06-10 22:18 UTCEPSS rescore
  47. 2026-06-10 13:22 UTCEPSS rescore
  48. 2026-06-08 14:16 UTCEPSS rescore
  49. 2026-06-08 14:16 UTCEPSS rescore
  50. 2026-06-07 15:24 UTCEPSS rescore
  51. 2026-06-05 22:46 UTCEPSS rescore
  52. 2026-06-05 22:46 UTCEPSS rescore
  53. 2026-06-05 06:10 UTCEPSS rescore
  54. 2026-06-05 06:10 UTCEPSS rescore
  55. 2026-06-04 13:12 UTCEPSS rescore
  56. 2026-06-04 13:12 UTCEPSS rescore
  57. 2026-06-02 20:12 UTCEPSS rescore
  58. 2026-06-01 13:51 UTCEPSS rescore
  59. 2026-06-01 13:51 UTCEPSS rescore
  60. 2026-05-31 22:30 UTCEPSS rescore
  61. 2026-05-31 22:30 UTCEPSS rescore
  62. 2026-05-31 00:16 UTCEPSS rescore
  63. 2026-05-29 22:14 UTCEG score recompute
  64. 2026-05-29 22:14 UTCVendor advisory
  65. 2026-05-29 22:14 UTCGHSA enrichment
  66. 2026-05-29 13:44 UTCEPSS rescore

Frequently asked(5)

What is CVE-2025-39852?
CVE-2025-39852 is a medium vulnerability published on September 19, 2025. In the Linux kernel, the following vulnerability has been resolved: net/tcp: Fix socket memory leak in TCP-AO failure handling for IPv6 When tcpaocopyallmatching() fails in tcpv6synrecvsock() it just exits the function. This ends up causing a memory-leak: unreferenced object 0xffff0000281a8200…
When was CVE-2025-39852 disclosed?
CVE-2025-39852 was first published in the National Vulnerability Database on September 19, 2025, with the most recent update on January 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-39852 actively exploited?
CVE-2025-39852 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.7% of all scored CVEs.
What is the CVSS score of CVE-2025-39852?
CVE-2025-39852 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-39852?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-39852, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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