CVE-2024-26704: ext4: fix double-free of blocks due to wrong extents moved_len
Vulnerability summary
CVE-2024-26704 is a high (CVSS 7.8) Double Free vulnerability in debian debian_linux. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 18.9% of scored vulnerabilities.
Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 39 · Related 28Timeline
- 03-04-2024PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: fix double-free of blocks due to wrong extents moved_len In ext4_move_extents(), moved_len is only updated when all moves are successfully executed, and only discards orig_inode and donor_inode preallocations when moved_len is not zero. When the loop fails to exit after successfully moving some extents, moved_len is not updated and remains at 0, so it does not discard the preallocations. If the moved extents overlap with the preallocated extents, the overlapped extents are freed twice in ext4_mb_release_inode_pa() and ext4_process_freed_data() (as described in commit 94d7c16cbbbd ("ext4: Fix double-free of blocks with EXT4_IOC_MOVE_EXT")), and bb_free is incremented twice. Hence when trim is executed, a zero-division bug is triggered in mb_update_avg_fragment_size() because bb_free is not zero and bb_fragments is zero. Therefore, update move_len after each extent move to avoid the issue.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.27%
Chance of exploitation in the next 30 days
Percentile
19%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.27% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu116 products
- linux< 4.4.0-254.288 | < 4.15.0-225.237 | < 5.4.0-181.201 | < 5.15.0-106.116
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 4.4.0-1131.137 | < 4.4.0-1169.184 | < 4.15.0-1168.181 | < 5.4.0-1124.134 | < 5.15.0-1061.67
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian2 products
- linux< 6.1.82-1 | < 6.7.7-1
- debian_linuxEOL10.0
Linux2 products
- linux≥ fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a, < b4fbb89d722cbb16beaaea234b7230faaaf68c71 | ≥ fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a, < afbcad9ae7d6d11608399188f03a837451b6b3a1 | ≥ fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a, < d033a555d9a1cf53dbf3301af7199cc4a4c8f537 | ≥ fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a, < afba9d11320dad5ce222ac8964caf64b7b4bedb1 | ≥ fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a, < 185eab30486ba3e7bf8b9c2e049c79a06ffd2bc1 | ≥ fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a, < 2883940b19c38d5884c8626483811acf4d7e148f | ≥ fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a, < 559ddacb90da1d8786dd8ec4fd76bbfa404eaef6 | ≥ fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a, < 55583e899a5357308274601364741a83e78d6ac4 | 3.18
- linux_kernel≥ 3.18, < 4.19.307 | ≥ 4.20, < 5.4.269 | ≥ 5.5, < 5.10.210 | ≥ 5.11, < 5.15.149 | ≥ 5.16, < 6.1.79 | ≥ 6.2, < 6.6.18 | ≥ 6.7, < 6.7.6 | 6.8:rc1 | 6.8:rc2
3 vendors · 120 products
