CVE-2026-45912ext4: don't cache extent during splitting extent

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: don't cache extent during splitting extent Caching extents during the splitting process is risky, as it may result in stale extents remaining in the status tree. Moreover, in most cases, the corresponding extent block entries are likely already cached before the split happens, making caching here not particularly useful. Assume we have an unwritten extent, and then DIO writes the first half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, when ext4_split_extent_at() splits this extent, it truncates the existing extent and then inserts a new one. During this process, this extent status entry may be shrunk, and calls to ext4_find_extent() and ext4_cache_extents() may occur, which could potentially insert the truncated range as a hole into the extent status tree. After the split is completed, this hole is not replaced with the correct status. [UUUUUUU|UUUUUUUU] on-disk extent U: unwritten extent [UUUUUUU|HHHHHHHH] extent status tree H: hole Then, the outer calling functions will not correct this remaining hole extent either. Finally, if we perform a delayed buffer write on this latter part, it will re-insert the delayed extent and cause an error in space accounting. In adition, if the unwritten extent cache is not shrunk during the splitting, ext4_cache_extents() also conflicts with existing extents when caching extents. In the future, we will add checks when caching extents, which will trigger a warning. Therefore, Do not cache extents that are being split.

Timeline

Scores

EPSS (exploitation in 30 days)

0.12% · top 98% of all CVEs (13 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.

Affected products

• Linux · Linux

  • affected 107a7bd31ac003e42c0f966aa8e5b26947de6024 – < 8302b5b4aacdbb378f7b1216bb2ee782b5142415
  • affected 107a7bd31ac003e42c0f966aa8e5b26947de6024 – < 692103feca376ae4298c92aa8828015d20f1d87b
  • affected 107a7bd31ac003e42c0f966aa8e5b26947de6024 – < 4c2d9dac4d328244f9365b0a1fa27ec802821820
  • affected 107a7bd31ac003e42c0f966aa8e5b26947de6024 – < 93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036
  • affected 107a7bd31ac003e42c0f966aa8e5b26947de6024 – < 96007fd3c106aea773c1afae2d6f64cceb6da208
  • affected 107a7bd31ac003e42c0f966aa8e5b26947de6024 – < 5b1f4290453314e11cd8e15c7baa8a9b76c19b23
  • affected 107a7bd31ac003e42c0f966aa8e5b26947de6024 – < 9a2b95cdaf07785e2739199037bd9c0863ccc1be
  • affected 107a7bd31ac003e42c0f966aa8e5b26947de6024 – < 8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79

• Linux · Linux

  • affected 3.12
  • unaffected < 3.12
  • unaffected 5.10.252 – ≤ 5.10.*
  • unaffected 5.15.202 – ≤ 5.15.*
  • unaffected 6.1.165 – ≤ 6.1.*
  • unaffected 6.6.128 – ≤ 6.6.*
  • unaffected 6.12.75 – ≤ 6.12.*
  • unaffected 6.18.14 – ≤ 6.18.*
  • unaffected 6.19.4 – ≤ 6.19.*
  • unaffected 7.0 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-32378 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-45912](https://cveledger.app/badge/CVE-2026-45912.svg)](https://cveledger.app/cve/CVE-2026-45912)

Record last updated 6 Nov 2026, 15:53 UTC.