ext4: fix corruption during on-line resize

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix corruption during on-line resize We observed a corruption during on-line resize of a file system that is larger than 16 TiB with 4k block size. With having more then 2^32 blocks resize_inode is turned off by default by mke2fs. The issue can be reproduced on a smaller file system for convenience by explicitly turning off resize_inode. An on-line resize across an 8 GiB boundary (the size of a meta block group in this setup) then leads to a corruption: dev=/dev/<some_dev> # should be >= 16 GiB mkdir -p /corruption /sbin/mke2fs -t ext4 -b 4096 -O ^resize_inode $dev $((2 * 2**21 - 2**15)) mount -t ext4 $dev /corruption dd if=/dev/zero bs=4096 of=/corruption/test count=$((2*2**21 - 4*2**15)) sha1sum /corruption/test # 79d2658b39dcfd77274e435b0934028adafaab11 /corruption/test /sbin/resize2fs $dev $((2*2**21)) # drop page cache to force reload the block from disk echo 1 > /proc/sys/vm/drop_caches sha1sum /corruption/test # 3c2abc63cbf1a94c9e6977e0fbd72cd832c4d5c3 /corruption/test 2^21 = 2^15*2^6 equals 8 GiB whereof 2^15 is the number of blocks per block group and 2^6 are the number of block groups that make a meta block group. The last checksum might be different depending on how the file is laid out across the physical blocks. The actual corruption occurs at physical block 63*2^15 = 2064384 which would be the location of the backup of the meta block group's block descriptor. During the on-line resize the file system will be converted to meta_bg starting at s_first_meta_bg which is 2 in the example - meaning all block groups after 16 GiB. However, in ext4_flex_group_add we might add block groups that are not part of the first meta block group yet. In the reproducer we achieved this by substracting the size of a whole block group from the point where the meta block group would start. This must be considered when updating the backup block group descriptors to follow the non-meta_bg layout. The fix is to add a test whether the group to add is already part of the meta block group or not.

Timeline

Scores

EPSS (exploitation in 30 days)

0.27% · top 80% of all CVEs (12 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 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < 75cc31c2e7193b69f5d25650bda5bb42ed92f8a1
  • affected 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < ee4e9c1976147a850f6085a13fca95bcaa00d84c
  • affected 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < e8e8b197317228b5089ed9e7802dadf3ccaa027a
  • affected 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < 239c669edb2bffa1aa2612519b1d438ab35d6be6
  • affected 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < fb1088d51bbaa0faec5a55d4f5818a9ab79e24df
  • affected 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < 37b6a3ba793bbbae057f5b991970ebcc52cb3db5
  • affected 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < b461910af8ba3bed80f48c2bf852686d05c6fc5c
  • affected 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < 722d2c01b8b108f8283d1b7222209d5b2a5aa7bd
  • affected 01f795f9e0d67adeccc61a8b20c28acb45fa5fd8 – < a6b3bfe176e8a5b05ec4447404e412c2a3fc92cc

• Linux · Linux

  • affected 3.7
  • unaffected < 3.7
  • unaffected 4.19.312 – ≤ 4.19.*
  • unaffected 5.4.274 – ≤ 5.4.*
  • unaffected 5.10.215 – ≤ 5.10.*
  • unaffected 5.15.154 – ≤ 5.15.*
  • unaffected 6.1.84 – ≤ 6.1.*
  • unaffected 6.6.24 – ≤ 6.6.*
  • unaffected 6.7.12 – ≤ 6.7.*
  • unaffected 6.8.3 – ≤ 6.8.*
  • unaffected 6.9 – ≤ *

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-2024-35799 (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-2024-35807](https://cveledger.app/badge/CVE-2024-35807.svg)](https://cveledger.app/cve/CVE-2024-35807)

Record last updated 15 Oct 2026, 00:40 UTC.