CVE-2026-45912: linux
Vulnerability summary
CVE-2026-45912 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.12% chance of exploitation in the next 30 days, higher than 1.9% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 37 · Related 37Timeline
- 27-05-2026PublishedVulnerability first disclosed.
- 30-05-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.12%
Chance of exploitation in the next 30 days
Percentile
2%
Versus all other CVEs
30-day change
0.00 pp
From 0.12% on 21-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu157 products
- linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-134.134
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1060.63
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 107a7bd31ac003e42c0f966aa8e5b26947de6024, < 8302b5b4aacdbb378f7b1216bb2ee782b5142415 | ≥ 107a7bd31ac003e42c0f966aa8e5b26947de6024, < 692103feca376ae4298c92aa8828015d20f1d87b | ≥ 107a7bd31ac003e42c0f966aa8e5b26947de6024, < 4c2d9dac4d328244f9365b0a1fa27ec802821820 | ≥ 107a7bd31ac003e42c0f966aa8e5b26947de6024, < 93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036 | ≥ 107a7bd31ac003e42c0f966aa8e5b26947de6024, < 96007fd3c106aea773c1afae2d6f64cceb6da208 | ≥ 107a7bd31ac003e42c0f966aa8e5b26947de6024, < 5b1f4290453314e11cd8e15c7baa8a9b76c19b23 | ≥ 107a7bd31ac003e42c0f966aa8e5b26947de6024, < 9a2b95cdaf07785e2739199037bd9c0863ccc1be | ≥ 107a7bd31ac003e42c0f966aa8e5b26947de6024, < 8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79 | 3.12
- linux_kernel≥ 3.12, < 5.10.252 | ≥ 5.11, < 5.15.202 | ≥ 5.16, < 6.1.165 | ≥ 6.2, < 6.6.128 | ≥ 6.7, < 6.12.75 | ≥ 6.13, < 6.18.14 | ≥ 6.19, < 6.19.4
Debian1 product
- linux< 6.1.170-1 | < 6.12.85-1 | < 6.18.14-1
3 vendors · 160 products
