CVE-2025-21887: ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up

Affected versions

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

• linux linux kernel5.10.188 and later · before 5.11
• linux linux kernel5.15.121 and later · before 5.15.179
• linux linux kernel6.1.39 and later · before 6.1.130
• linux linux kernel6.3.13 and later · before 6.4
• linux linux kernel6.4.4 and later · before 6.6.81
• linux linux kernel6.7 and later · before 6.12.18
• linux linux kernel6.13 and later · before 6.13.6
• linux linux kernel6.14

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

  • 33ab4dd6202f359558a0a2678b94d1b9994c17e5, 1ecdc55e5cd9f70f8d7513802971d4cffb9f77af, 6.5affected
  • 714ba10a6dd19752a349e59aa875f3288ccb59b9 and later · before f77618291836168eca99e89cd175256f928f5e64affected · git
  • 62f29ca45f832e281fc14966ac25f6ff3bd121ca and later · before 4b49d939b5a79117f939b77cc67efae2694d9799affected · git
  • e4f2a1feebb3f209a0fca82aa53507a5b8be4d53 and later · before a7c41830ffcd17b2177a95a9b99b270302090c35affected · git
  • b07d5cc93e1b28df47a72c519d09d0a836043613 and later · before 64455c8051c3aedc71abb7ec8d47c80301f99f00affected · git
  • b07d5cc93e1b28df47a72c519d09d0a836043613 and later · before 3594aad97e7be2557ca9fa9c931b206b604028c8affected · git
  • b07d5cc93e1b28df47a72c519d09d0a836043613 and later · before 60b4b5c1277fc491da9e1e7abab307bfa39c2db7affected · git
  • b07d5cc93e1b28df47a72c519d09d0a836043613 and later · before c84e125fff2615b4d9c259e762596134eddd2f27affected · git
  • 5.10.188 and later · before 5.10.247affected · semver
  • 5.15.121 and later · before 5.15.179affected · 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-2025-21885Mar 27, 2025 · RDMA/bnxt_re: Fix the page details for the srq created by kernel consumers
  22Monitor
• ← EarlierCVE-2025-21886Mar 27, 2025 · RDMA/mlx5: Fix implicit ODP hang on parent deregistration
  22Monitor
• Later →CVE-2025-21888Mar 27, 2025 · RDMA/mlx5: Fix a WARN during dereg_mr for DM type
  22Monitor

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.