CVE-2026-43364

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-05-08. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: 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:

ublk: fix NULL pointer dereference in ublk_ctrl_set_size()

ublk_ctrl_set_size() unconditionally dereferences ub->ub_disk via set_capacity_and_notify() without checking if it is NULL.

ub->ub_disk is NULL before UBLK_CMD_START_DEV completes (it is only assigned in ublk_ctrl_start_dev()) and after UBLK_CMD_STOP_DEV runs (ublk_detach_disk() sets it to NULL). Since the UBLK_CMD_UPDATE_SIZE handler performs no state validation, a user can trigger a NULL pointer dereference by sending UPDATE_SIZE to a device that has been added but not yet started, or one that has been stopped.

Fix this by checking ub->ub_disk under ub->mutex before dereferencing it, and returning -ENODEV if the disk is not available.

CVSS v3
5.5
EG Score
5.5(medium)
EPSS
2.2%
KEV
Not listed

Published

May 8, 2026

Last Modified

May 15, 2026

Advisory Details (3)

Auto-updated May 15, 2026
No patch confirmed yet.
generic

ublk: fix NULL pointer dereference in ublk_ctrl_set_size() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f13fe6794726755a43090cb680c4c58cea6aa5f1
generic

ublk: fix NULL pointer dereference in ublk_ctrl_set_size() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c28d945bfa92e15147e93b73f95345b9bec979b0
generic

ublk: fix NULL pointer dereference in ublk_ctrl_set_size() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/25966fc097691e5c925ad080f64a2f19c5fd940a

Vendor Advisories for CVE-2026-43364(1)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.18.20—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 8× in last 7d / 32× 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. 2026-07-16 17:03 UTCEPSS rescore
  2. 2026-07-16 05:23 UTCOSV refresh
  3. 2026-07-15 16:57 UTCEPSS rescore
  4. 2026-07-15 02:00 UTCEPSS rescore
  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. 2026-07-05 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
  18. 2026-06-28 14:07 UTCEPSS rescore
  19. 2026-06-28 04:58 UTCGHSA enrichment
  20. 2026-06-28 04:56 UTCEPSS rescore
  21. 2026-06-27 03:08 UTCEPSS rescore
  22. 2026-06-26 21:27 UTCGHSA enrichment
  23. 2026-06-25 13:49 UTCEPSS rescore
  24. 2026-06-25 13:49 UTCEPSS rescore
  25. 2026-06-24 14:05 UTCEPSS rescore
Show 62 more
  1. 2026-06-23 21:33 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. 2026-06-17 01:49 UTCGHSA enrichment
  10. 2026-06-16 17:52 UTCEPSS rescore
  11. 2026-06-15 17:49 UTCEPSS rescore
  12. 2026-06-15 04:01 UTCGHSA enrichment
  13. 2026-06-14 02:53 UTCGHSA enrichment
  14. 2026-06-13 23:00 UTCEPSS rescore
  15. 2026-06-12 23:12 UTCEPSS rescore
  16. 2026-06-12 23:12 UTCEPSS rescore
  17. 2026-06-12 01:40 UTCGHSA enrichment
  18. 2026-06-11 14:00 UTCEPSS rescore
  19. 2026-06-11 00:32 UTCGHSA enrichment
  20. 2026-06-10 22:18 UTCEPSS rescore
  21. 2026-06-10 13:22 UTCEPSS rescore
  22. 2026-06-10 13:22 UTCEPSS rescore
  23. 2026-06-09 22:45 UTCGHSA enrichment
  24. 2026-06-08 20:45 UTCGHSA enrichment
  25. 2026-06-08 14:17 UTCEPSS rescore
  26. 2026-06-08 14:17 UTCEPSS rescore
  27. 2026-06-07 15:25 UTCEPSS rescore
  28. 2026-06-07 15:25 UTCEPSS rescore
  29. 2026-06-07 14:36 UTCGHSA enrichment
  30. 2026-06-06 13:47 UTCEPSS rescore
  31. 2026-06-06 13:47 UTCEPSS rescore
  32. 2026-06-06 13:29 UTCGHSA enrichment
  33. 2026-06-05 22:47 UTCEPSS rescore
  34. 2026-06-05 12:21 UTCGHSA enrichment
  35. 2026-06-05 06:10 UTCEPSS rescore
  36. 2026-06-05 06:10 UTCEPSS rescore
  37. 2026-06-04 13:12 UTCEPSS rescore
  38. 2026-06-04 13:12 UTCEPSS rescore
  39. 2026-06-04 11:14 UTCGHSA enrichment
  40. 2026-06-03 10:06 UTCGHSA enrichment
  41. 2026-06-02 20:13 UTCEPSS rescore
  42. 2026-06-02 08:58 UTCGHSA enrichment
  43. 2026-06-01 13:52 UTCEPSS rescore
  44. 2026-06-01 13:52 UTCEPSS rescore
  45. 2026-06-01 07:51 UTCGHSA enrichment
  46. 2026-05-31 22:30 UTCEPSS rescore
  47. 2026-05-31 22:30 UTCEPSS rescore
  48. 2026-05-31 00:16 UTCEPSS rescore
  49. 2026-05-31 00:16 UTCEPSS rescore
  50. 2026-05-29 13:44 UTCEPSS rescore
  51. 2026-05-29 13:44 UTCEPSS rescore
  52. 2026-05-28 13:44 UTCEPSS rescore
  53. 2026-05-28 13:44 UTCEPSS rescore
  54. 2026-05-27 13:40 UTCEPSS rescore
  55. 2026-05-27 13:40 UTCEPSS rescore
  56. 2026-05-26 13:44 UTCEPSS rescore
  57. 2026-05-26 07:18 UTCEPSS rescore
  58. 2026-05-21 22:43 UTCEPSS rescore
  59. 2026-05-20 22:38 UTCEPSS rescore
  60. 2026-05-20 13:40 UTCEG score recompute
  61. 2026-05-20 13:40 UTCGHSA enrichment
  62. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-43364?
CVE-2026-43364 is a medium vulnerability published on May 8, 2026. In the Linux kernel, the following vulnerability has been resolved: ublk: fix NULL pointer dereference in ublkctrlset_size() ublkctrlsetsize() unconditionally dereferences ub->ubdisk via setcapacityand_notify() without checking if it is NULL. ub->ubdisk is NULL before UBLKCMDSTARTDEV completes (it…
When was CVE-2026-43364 disclosed?
CVE-2026-43364 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-2026-43364 actively exploited?
CVE-2026-43364 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-43364?
CVE-2026-43364 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-43364?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43364, 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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