CVE-2026-31446: ext4: fix use-after-free in update_super_work when racing with umount

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• linux linux kernel5.10.114 and later · before 5.11
• linux linux kernel5.15.38 and later · before 5.15.203
• linux linux kernel5.17.6 and later · before 5.18
• linux linux kernel5.18.1 and later · before 6.1.168
• linux linux kernel6.2 and later · before 6.6.131
• linux linux kernel6.7 and later · before 6.12.80
• linux linux kernel6.13 and later · before 6.18.21
• linux linux kernel6.19 and later · before 6.19.11
• linux linux kernel5.18
• linux linux kernel7.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

• Linux Linux

  • 585ef03c9e79672781f954daae730dfe24bf3a46, afe490e48d47df1b3f64012835c1bc2f075a8c8b, 5.18affected
  • 52c3a04f9ec2a16a4204d6274db338cb8d5b2d74 and later · before c8fe17a1b308c3d8c703ebfb049b325f844342c3affected · git
  • b98535d091795a79336f520b0708457aacf55c67 and later · before c4d829737329f2290dd41e290b7d75effdb2a7ffaffected · git
  • b98535d091795a79336f520b0708457aacf55c67 and later · before 9449f99ba04f5dd1c8423ad8a90b3651d7240d1daffected · git
  • b98535d091795a79336f520b0708457aacf55c67 and later · before 034053378dd81837fd6c7a43b37ee2e58d4f0b4eaffected · git
  • b98535d091795a79336f520b0708457aacf55c67 and later · before c97e282f7bfd0c3554c63d289964a5ca6a1d2ffeaffected · git
  • b98535d091795a79336f520b0708457aacf55c67 and later · before 08b10e6f37fc533a759e9833af0692242e8b3f93affected · git
  • b98535d091795a79336f520b0708457aacf55c67 and later · before d15e4b0a418537aafa56b2cb80d44add83e83697affected · git
  • 5.15.38 and later · before 5.15.203affected · semver
  • 5.10.114 and later · before 5.11affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
  90Now
• CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
  89Now
• CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
  85Now

Published before and after this one in the same product

• ← EarlierCVE-2026-31442Apr 22, 2026 · dmaengine: idxd: Fix possible invalid memory access after FLR
  31Monitor
• ← EarlierCVE-2026-31443Apr 22, 2026 · dmaengine: idxd: Fix crash when the event log is disabled
  22Monitor
• Later →CVE-2026-31447Apr 22, 2026 · ext4: reject mount if bigalloc with s_first_data_block != 0
  31Monitor

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1free(dev->buf);2/* ... another thread is still running ... */3process(dev->buf);

1lock(&dev->lock);2free(dev->buf);3dev->buf = NULL;4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.