CVE-2026-43376

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-05-08. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.8Exploit: 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:

ksmbd: fix use-after-free by using call_rcu() for oplock_info

ksmbd currently frees oplock_info immediately using kfree(), even though it is accessed under RCU read-side critical sections in places like opinfo_get() and proc_show_files().

Since there is no RCU grace period delay between nullifying the pointer and freeing the memory, a reader can still access oplock_info structure after it has been freed. This can leads to a use-after-free especially in opinfo_get() where atomic_inc_not_zero() is called on already freed memory.

Fix this by switching to deferred freeing using call_rcu().

CVSS v3
9.8
EG Score
9.8(medium)
EPSS
35.9%
KEV
Not listed

Published

May 8, 2026

Last Modified

May 15, 2026

Advisory Details (5)

Auto-updated Jun 21, 2026
No patch confirmed yet.
generic

ksmbd: fix use-after-free by using call_rcu() for oplock_info - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde
generic

ksmbd: fix use-after-free by using call_rcu() for oplock_info - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a
generic

ksmbd: fix use-after-free by using call_rcu() for oplock_info - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294
generic

ksmbd: fix use-after-free by using call_rcu() for oplock_info - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e
generic

ksmbd: fix use-after-free by using call_rcu() for oplock_info - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c

Vendor Advisories for CVE-2026-43376(1)

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 7× in last 7d / 45× 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 261 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-43376?
CVE-2026-43376 is a critical vulnerability published on May 8, 2026. In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free by using callrcu() for oplockinfo ksmbd currently frees oplock_info immediately using kfree(), even though it is accessed under RCU read-side critical sections in places like opinfoget() and…
When was CVE-2026-43376 disclosed?
CVE-2026-43376 was first published in the National Vulnerability Database on May 8, 2026, with the most recent update on May 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43376 actively exploited?
CVE-2026-43376 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 35.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-43376?
CVE-2026-43376 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-43376?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43376, 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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