CVE-2026-31665

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-04-24. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

netfilter: nft_ct: fix use-after-free in timeout object destroy

nft_ct_timeout_obj_destroy() frees the timeout object with kfree() immediately after nf_ct_untimeout(), without waiting for an RCU grace period. Concurrent packet processing on other CPUs may still hold RCU-protected references to the timeout object obtained via rcu_dereference() in nf_ct_timeout_data().

Add an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer freeing until after an RCU grace period, matching the approach already used in nfnetlink_cttimeout.c.

KASAN report: BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0 Read of size 4 at addr ffff8881035fe19c by task exploit/80

Call Trace: nf_conntrack_tcp_packet+0x1381/0x29d0 nf_conntrack_in+0x612/0x8b0 nf_hook_slow+0x70/0x100 __ip_local_out+0x1b2/0x210 tcp_sendmsg_locked+0x722/0x1580 __sys_sendto+0x2d8/0x320

Allocated by task 75: nft_ct_timeout_obj_init+0xf6/0x290 nft_obj_init+0x107/0x1b0 nf_tables_newobj+0x680/0x9c0 nfnetlink_rcv_batch+0xc29/0xe00

Freed by task 26: nft_obj_destroy+0x3f/0xa0 nf_tables_trans_destroy_work+0x51c/0x5c0 process_one_work+0x2c4/0x5a0

CVSS v3
7.8
EG Score
7.8(medium)
EPSS
2.4%
KEV
Not listed

Published

April 24, 2026

Last Modified

July 14, 2026

Advisory Details (8)

Auto-updated Jun 4, 2026
No patch confirmed yet.
generic

netfilter: nft_ct: fix use-after-free in timeout object destroy - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f8dca15a1b190787bbd03285304b569631160eda
generic

netfilter: nft_ct: fix use-after-free in timeout object destroy - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f16fe84879a5280f05ebbcea593a189ba0f3e79a
generic

netfilter: nft_ct: fix use-after-free in timeout object destroy - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d0983b48c10d1509fd795c155f8b1e832e1369ff
generic

netfilter: nft_ct: fix use-after-free in timeout object destroy - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c581e5c8f2b59158f62efe61c1a3dc36189081ff
generic

netfilter: nft_ct: fix use-after-free in timeout object destroy - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c458fc1c278a65ad5381083121d39a479973ebed
generic

netfilter: nft_ct: fix use-after-free in timeout object destroy - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b42aca3660dc2627a29a38131597ca610dc451f9
generic

netfilter: nft_ct: fix use-after-free in timeout object destroy - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77
generic

netfilter: nft_ct: fix use-after-free in timeout object destroy - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/070abdf1b04325b21a20a2a0c39a2208af107275

Vendor Advisories for CVE-2026-31665(2)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 37× 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.

Showing the most recent 100 of 156 total refreshes for this CVE.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-13 22:30 UTCEPSS rescore
  4. 2026-07-13 06:13 UTCEPSS rescore
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  6. 2026-07-12 05:46 UTCEPSS rescore
  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-08 15:15 UTCEPSS rescore
  10. 2026-07-07 13:46 UTCEPSS rescore
  11. 2026-07-06 16:27 UTCEPSS rescore
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  13. 2026-07-05 02:30 UTCEPSS rescore
  14. 2026-07-04 06:31 UTCEPSS rescore
  15. 2026-07-01 15:06 UTCEPSS rescore
  16. 2026-06-30 23:22 UTCEPSS rescore
  17. 2026-06-29 14:06 UTCEPSS rescore
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  19. 2026-06-28 14:07 UTCEPSS rescore
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  21. 2026-06-28 04:56 UTCEPSS rescore
  22. 2026-06-28 04:56 UTCEPSS rescore
  23. 2026-06-27 03:08 UTCEPSS rescore
  24. 2026-06-25 13:49 UTCEPSS rescore
  25. 2026-06-25 13:49 UTCEPSS rescore
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  1. 2026-06-24 14:05 UTCEPSS rescore
  2. 2026-06-22 14:25 UTCEPSS rescore
  3. 2026-06-22 14:25 UTCEPSS rescore
  4. 2026-06-21 14:56 UTCEPSS rescore
  5. 2026-06-21 14:56 UTCEPSS rescore
  6. 2026-06-21 01:59 UTCEPSS rescore
  7. 2026-06-19 19:25 UTCEPSS rescore
  8. 2026-06-19 19:25 UTCEPSS rescore
  9. 2026-06-18 17:52 UTCEPSS rescore
  10. 2026-06-18 17:52 UTCEPSS rescore
  11. 2026-06-17 17:53 UTCEPSS rescore
  12. 2026-06-16 17:52 UTCEPSS rescore
  13. 2026-06-15 17:49 UTCEPSS rescore
  14. 2026-06-15 01:53 UTCEG score recompute
  15. 2026-06-15 01:53 UTCVendor advisory
  16. 2026-06-15 01:53 UTCGHSA enrichment
  17. 2026-06-14 23:18 UTCEPSS rescore
  18. 2026-06-14 11:47 UTCEG score recompute
  19. 2026-06-14 11:47 UTCVendor advisory
  20. 2026-06-14 11:47 UTCGHSA enrichment
  21. 2026-06-13 23:00 UTCEPSS rescore
  22. 2026-06-12 23:12 UTCEPSS rescore
  23. 2026-06-12 23:12 UTCEPSS rescore
  24. 2026-06-12 02:02 UTCEG score recompute
  25. 2026-06-12 02:02 UTCVendor advisory
  26. 2026-06-12 02:02 UTCGHSA enrichment
  27. 2026-06-11 14:00 UTCEPSS rescore
  28. 2026-06-11 13:34 UTCEG score recompute
  29. 2026-06-11 13:34 UTCVendor advisory
  30. 2026-06-11 13:34 UTCGHSA enrichment
  31. 2026-06-10 22:18 UTCEPSS rescore
  32. 2026-06-10 13:57 UTCEG score recompute
  33. 2026-06-10 13:57 UTCVendor advisory
  34. 2026-06-10 13:57 UTCGHSA enrichment
  35. 2026-06-10 13:22 UTCEPSS rescore
  36. 2026-06-10 01:30 UTCEG score recompute
  37. 2026-06-10 01:30 UTCVendor advisory
  38. 2026-06-10 01:30 UTCGHSA enrichment
  39. 2026-06-09 13:03 UTCEG score recompute
  40. 2026-06-09 13:03 UTCVendor advisory
  41. 2026-06-09 13:03 UTCGHSA enrichment
  42. 2026-06-09 00:36 UTCEG score recompute
  43. 2026-06-09 00:36 UTCVendor advisory
  44. 2026-06-09 00:36 UTCGHSA enrichment
  45. 2026-06-08 14:17 UTCEPSS rescore
  46. 2026-06-08 14:17 UTCEPSS rescore
  47. 2026-06-08 08:58 UTCEG score recompute
  48. 2026-06-08 08:58 UTCVendor advisory
  49. 2026-06-08 08:58 UTCGHSA enrichment
  50. 2026-06-07 20:30 UTCEG score recompute
  51. 2026-06-07 20:30 UTCVendor advisory
  52. 2026-06-07 20:30 UTCGHSA enrichment
  53. 2026-06-07 15:25 UTCEPSS rescore
  54. 2026-06-07 15:25 UTCEPSS rescore
  55. 2026-06-07 15:25 UTCEPSS rescore
  56. 2026-06-07 08:03 UTCEG score recompute
  57. 2026-06-07 08:03 UTCVendor advisory
  58. 2026-06-07 08:03 UTCGHSA enrichment
  59. 2026-06-06 19:36 UTCEG score recompute
  60. 2026-06-06 19:36 UTCVendor advisory
  61. 2026-06-06 19:36 UTCGHSA enrichment
  62. 2026-06-06 13:47 UTCEPSS rescore
  63. 2026-06-06 13:47 UTCEPSS rescore
  64. 2026-06-06 06:39 UTCEG score recompute
  65. 2026-06-06 06:39 UTCVendor advisory
  66. 2026-06-06 06:39 UTCGHSA enrichment
  67. 2026-06-05 22:47 UTCEPSS rescore
  68. 2026-06-05 22:47 UTCEPSS rescore
  69. 2026-06-05 18:09 UTCEG score recompute
  70. 2026-06-05 18:09 UTCVendor advisory
  71. 2026-06-05 18:09 UTCGHSA enrichment
  72. 2026-06-05 05:06 UTCEG score recompute
  73. 2026-06-05 05:06 UTCVendor advisory
  74. 2026-06-05 05:06 UTCGHSA enrichment
  75. 2026-06-04 16:12 UTCEG score recompute

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Frequently asked(5)

What is CVE-2026-31665?
CVE-2026-31665 is a high vulnerability published on April 24, 2026. In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_ct: fix use-after-free in timeout object destroy nftcttimeoutobjdestroy() frees the timeout object with kfree() immediately after nfctuntimeout(), without waiting for an RCU grace period. Concurrent packet processing…
When was CVE-2026-31665 disclosed?
CVE-2026-31665 was first published in the National Vulnerability Database on April 24, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31665 actively exploited?
CVE-2026-31665 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-31665?
CVE-2026-31665 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-31665?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31665, 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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