CVE-2026-43027

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-05-01. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
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

A fix is available — apply it.

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

netfilter: nf_conntrack_helper: pass helper to expect cleanup

nf_conntrack_helper_unregister() calls nf_ct_expect_iterate_destroy() to remove expectations belonging to the helper being unregistered. However, it passes NULL instead of the helper pointer as the data argument, so expect_iter_me() never matches any expectation and all of them survive the cleanup.

After unregister returns, nfnl_cthelper_del() frees the helper object immediately. Subsequent expectation dumps or packet-driven init_conntrack() calls then dereference the freed exp->helper, causing a use-after-free.

Pass the actual helper pointer so expectations referencing it are properly destroyed before the helper object is freed.

BUG: KASAN: slab-use-after-free in string+0x38f/0x430 Read of size 1 at addr ffff888003b14d20 by task poc/103 Call Trace: string+0x38f/0x430 vsnprintf+0x3cc/0x1170 seq_printf+0x17a/0x240 exp_seq_show+0x2e5/0x560 seq_read_iter+0x419/0x1280 proc_reg_read+0x1ac/0x270 vfs_read+0x179/0x930 ksys_read+0xef/0x1c0 Freed by task 103: The buggy address is located 32 bytes inside of freed 192-byte region [ffff888003b14d00, ffff888003b14dc0)

CVSS v3
7.8
EG Score
7.8(medium)
EPSS
3.1%
KEV
Not listed

Published

May 1, 2026

Last Modified

July 14, 2026

Advisory Details (8)

Auto-updated May 8, 2026
No patch confirmed yet.
generic

netfilter: nf_conntrack_helper: pass helper to expect cleanup - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/dc1739eff48e34cc71d4e2f03715493fbcebd8af
generic

netfilter: nf_conntrack_helper: pass helper to expect cleanup - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a242a9ae58aa46ff7dae51ce64150a93957abe65
generic

netfilter: nf_conntrack_helper: pass helper to expect cleanup - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/90bd7e8501349db3006d21fbc09df9ffcb172965
generic

netfilter: nf_conntrack_helper: pass helper to expect cleanup - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/620f3d14c1ef51d425060a3056ad8dbae8f998a3
generic

netfilter: nf_conntrack_helper: pass helper to expect cleanup - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5cf28d5c8dcbbe8af6d3b145babe491906d7bad1
generic

netfilter: nf_conntrack_helper: pass helper to expect cleanup - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/504ba4168466c91210c45acdc332479cfd5f2da6
generic

netfilter: nf_conntrack_helper: pass helper to expect cleanup - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2cf2737c85a2ba2b52024dafe68ffad2676f97be
generic

netfilter: nf_conntrack_helper: pass helper to expect cleanup - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2c16e4d64dd91227742dfe196a3e7b0568bef65a

Vendor Advisories for CVE-2026-43027(9)

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

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatkernel-0:6.12.0-211.18.1.el10_22026-05-28redhat
redhatkernel-rt-0:4.18.0-553.126.1.rt7.467.el8_102026-05-28redhat
redhatkernel-0:4.18.0-553.126.1.el8_102026-05-28redhat
redhatkernel-0:5.14.0-687.12.1.el9_82026-05-28redhat

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.

Data Freshness Timeline

(refreshed 9× in last 7d / 34× 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 150 total refreshes for this CVE.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 02:00 UTCEPSS rescore
  3. 2026-07-14 13:19 UTCNVD updateCVSS v3 → 7.8 · severity → HIGH
  4. 2026-07-14 13:11 UTCMITRE cvelistV5
  5. 2026-07-13 22:30 UTCEPSS rescore
  6. 2026-07-13 06:13 UTCEPSS rescore
  7. 2026-07-12 05:46 UTCEPSS rescore
  8. 2026-07-11 08:27 UTCEPSS rescore
  9. 2026-07-09 19:10 UTCEPSS rescore
  10. 2026-07-08 15:16 UTCEPSS rescore
  11. 2026-07-07 13:46 UTCEPSS rescore
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-06 02:23 UTCEPSS rescore
  14. 2026-07-06 02:23 UTCEPSS rescore
  15. 2026-07-05 02:30 UTCEPSS rescore
  16. 2026-07-04 06:31 UTCEPSS rescore
  17. 2026-07-01 15:06 UTCEPSS rescore
  18. 2026-06-29 14:06 UTCEPSS rescore
  19. 2026-06-28 14:07 UTCEPSS rescore
  20. 2026-06-27 03:08 UTCEPSS rescore
  21. 2026-06-25 13:49 UTCEPSS rescore
  22. 2026-06-25 13:49 UTCEPSS rescore
  23. 2026-06-24 14:05 UTCEPSS rescore
  24. 2026-06-23 21:33 UTCEPSS rescore
  25. 2026-06-22 14:25 UTCEPSS rescore
Show 75 more
  1. 2026-06-22 14:25 UTCEPSS rescore
  2. 2026-06-21 14:56 UTCEPSS rescore
  3. 2026-06-21 14:56 UTCEPSS rescore
  4. 2026-06-21 01:59 UTCEPSS rescore
  5. 2026-06-19 19:25 UTCEPSS rescore
  6. 2026-06-18 17:52 UTCEPSS rescore
  7. 2026-06-18 17:52 UTCEPSS rescore
  8. 2026-06-17 17:53 UTCEPSS rescore
  9. 2026-06-16 17:52 UTCEPSS rescore
  10. 2026-06-15 17:49 UTCEPSS rescore
  11. 2026-06-14 19:51 UTCEG score recompute
  12. 2026-06-14 19:51 UTCVendor advisory
  13. 2026-06-14 19:51 UTCGHSA enrichment
  14. 2026-06-14 08:51 UTCEG score recompute
  15. 2026-06-14 08:51 UTCVendor advisory
  16. 2026-06-14 08:51 UTCGHSA enrichment
  17. 2026-06-13 23:00 UTCEPSS rescore
  18. 2026-06-12 23:12 UTCEPSS rescore
  19. 2026-06-12 23:12 UTCEPSS rescore
  20. 2026-06-12 07:30 UTCEG score recompute
  21. 2026-06-12 07:30 UTCVendor advisory
  22. 2026-06-12 07:30 UTCGHSA enrichment
  23. 2026-06-11 20:28 UTCEG score recompute
  24. 2026-06-11 20:28 UTCVendor advisory
  25. 2026-06-11 20:28 UTCGHSA enrichment
  26. 2026-06-11 14:00 UTCEPSS rescore
  27. 2026-06-11 09:28 UTCEG score recompute
  28. 2026-06-11 09:28 UTCVendor advisory
  29. 2026-06-11 09:28 UTCGHSA enrichment
  30. 2026-06-10 22:18 UTCEPSS rescore
  31. 2026-06-10 21:40 UTCEG score recompute
  32. 2026-06-10 21:40 UTCVendor advisory
  33. 2026-06-10 21:40 UTCGHSA enrichment
  34. 2026-06-10 13:22 UTCEPSS rescore
  35. 2026-06-10 13:22 UTCEPSS rescore
  36. 2026-06-10 10:40 UTCEG score recompute
  37. 2026-06-10 10:40 UTCVendor advisory
  38. 2026-06-10 10:40 UTCGHSA enrichment
  39. 2026-06-09 23:24 UTCEG score recompute
  40. 2026-06-09 23:24 UTCVendor advisory
  41. 2026-06-09 23:24 UTCGHSA enrichment
  42. 2026-06-09 10:15 UTCEG score recompute
  43. 2026-06-09 10:15 UTCVendor advisory
  44. 2026-06-09 10:15 UTCGHSA enrichment
  45. 2026-06-08 23:15 UTCEG score recompute
  46. 2026-06-08 23:15 UTCVendor advisory
  47. 2026-06-08 23:15 UTCGHSA enrichment
  48. 2026-06-08 14:17 UTCEPSS rescore
  49. 2026-06-08 14:17 UTCEPSS rescore
  50. 2026-06-08 07:42 UTCEG score recompute
  51. 2026-06-08 07:42 UTCVendor advisory
  52. 2026-06-08 07:42 UTCGHSA enrichment
  53. 2026-06-07 20:42 UTCEG score recompute
  54. 2026-06-07 20:42 UTCVendor advisory
  55. 2026-06-07 20:42 UTCGHSA enrichment
  56. 2026-06-07 15:25 UTCEPSS rescore
  57. 2026-06-07 15:25 UTCEPSS rescore
  58. 2026-06-07 09:42 UTCEG score recompute
  59. 2026-06-07 09:42 UTCVendor advisory
  60. 2026-06-07 09:42 UTCGHSA enrichment
  61. 2026-06-06 22:42 UTCEG score recompute
  62. 2026-06-06 22:42 UTCVendor advisory
  63. 2026-06-06 22:42 UTCGHSA enrichment
  64. 2026-06-06 13:47 UTCEPSS rescore
  65. 2026-06-06 13:47 UTCEPSS rescore
  66. 2026-06-06 11:40 UTCEG score recompute
  67. 2026-06-06 11:40 UTCVendor advisory
  68. 2026-06-06 11:40 UTCGHSA enrichment
  69. 2026-06-06 00:39 UTCEG score recompute
  70. 2026-06-06 00:39 UTCVendor advisory
  71. 2026-06-06 00:39 UTCGHSA enrichment
  72. 2026-06-05 22:47 UTCEPSS rescore
  73. 2026-06-05 13:38 UTCEG score recompute
  74. 2026-06-05 13:38 UTCVendor advisory
  75. 2026-06-05 13:38 UTCGHSA enrichment

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-43027?
CVE-2026-43027 is a high vulnerability published on May 1, 2026. In the Linux kernel, the following vulnerability has been resolved: netfilter: nfconntrackhelper: pass helper to expect cleanup nfconntrackhelperunregister() calls nfctexpectiterate_destroy() to remove expectations belonging to the helper being unregistered. However, it passes NULL instead of the…
When was CVE-2026-43027 disclosed?
CVE-2026-43027 was first published in the National Vulnerability Database on May 1, 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-2026-43027 actively exploited?
CVE-2026-43027 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-43027?
CVE-2026-43027 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-43027?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43027, 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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