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
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(12)

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

Patch Availability(5)

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
linuxKernel @ 5.10.253—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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 31× 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 131 total refreshes for this CVE.

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

Related CVEs(same product + 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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