CVE-2026-31666

HIGHNVD 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
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 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:

btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()

After commit 1618aa3c2e01 ("btrfs: simplify return variables in lookup_extent_data_ref()"), the err and ret variables were merged into a single ret variable. However, when btrfs_next_leaf() returns 0 (success), ret is overwritten from -ENOENT to 0. If the first key in the next leaf does not match (different objectid or type), the function returns 0 instead of -ENOENT, making the caller believe the lookup succeeded when it did not. This can lead to operations on the wrong extent tree item, potentially causing extent tree corruption.

Fix this by returning -ENOENT directly when the key does not match, instead of relying on the ret variable.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

April 24, 2026

Last Modified

April 27, 2026

Advisory Details (4)

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

btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ab1e022379c3c811aa72da8eb0c7507859a1d0f5
generic

btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/450e6a685d0cad95b15f8af152057bd0bf79f50b
generic

btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4125a194db4a6cf91f619f38788272651cb97dce
generic

btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/316fb1b3169efb081d2db910cbbfef445afa03b9

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.12.82—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.

Data Freshness Timeline

(refreshed 12× 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 126 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-31666?
CVE-2026-31666 is a high vulnerability published on April 24, 2026. In the Linux kernel, the following vulnerability has been resolved: btrfs: fix incorrect return value after changing leaf in lookupextentdata_ref() After commit 1618aa3c2e01 ("btrfs: simplify return variables in lookupextentdata_ref()"), the err and ret variables were merged into a single ret…
When was CVE-2026-31666 disclosed?
CVE-2026-31666 was first published in the National Vulnerability Database on April 24, 2026, with the most recent update on April 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31666 actively exploited?
CVE-2026-31666 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.9% of all scored CVEs.
What is the CVSS score of CVE-2026-31666?
CVE-2026-31666 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-31666?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31666, 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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