CVE-2024-35798btrfs: fix race in read_extent_buffer_pages()
- 7.8HighCVSS base score
- 0.18%Exploitation in 30 daysEPSS · top 92% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix race in read_extent_buffer_pages() There are reports from tree-checker that detects corrupted nodes, without any obvious pattern so possibly an overwrite in memory. After some debugging it turns out there's a race when reading an extent buffer the uptodate status can be missed. To prevent concurrent reads for the same extent buffer, read_extent_buffer_pages() performs these checks: /* (1) */ if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags)) return 0; /* (2) */ if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags)) goto done; At this point, it seems safe to start the actual read operation. Once that completes, end_bbio_meta_read() does /* (3) */ set_extent_buffer_uptodate(eb); /* (4) */ clear_bit(EXTENT_BUFFER_READING, &eb->bflags); Normally, this is enough to ensure only one read happens, and all other callers wait for it to finish before returning. Unfortunately, there is a racey interleaving: Thread A | Thread B | Thread C ---------+----------+--------- (1) | | | (1) | (2) | | (3) | | (4) | | | (2) | | | (1) When this happens, thread B kicks of an unnecessary read. Worse, thread C will see UPTODATE set and return immediately, while the read from thread B is still in progress. This race could result in tree-checker errors like this as the extent buffer is concurrently modified: BTRFS critical (device dm-0): corrupted node, root=256 block=8550954455682405139 owner mismatch, have 11858205567642294356 expect [256, 18446744073709551360] Fix it by testing UPTODATE again after setting the READING bit, and if it's been set, skip the unnecessary read. [ minor update of changelog ]
Timeline
ID reserved
By Linux
Published
- 2 years later
· 2 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Medium4.7 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.18% · top 92% of all CVEs (14 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: High 7.8.
Affected products
- affected d7172f52e9933b6ec9305e7fe6e829e3939dba04 – < 0427c8ef8bbb7f304de42ef51d69c960e165e052
- affected d7172f52e9933b6ec9305e7fe6e829e3939dba04 – < 3a25878a3378adce5d846300c9570f15aa7f7a80
- affected d7172f52e9933b6ec9305e7fe6e829e3939dba04 – < 2885d54af2c2e1d910e20d5c8045bae40e02fbc1
- affected d7172f52e9933b6ec9305e7fe6e829e3939dba04 – < ef1e68236b9153c27cb7cf29ead0c532870d4215
- affected 6.5
- unaffected < 6.5
- unaffected 6.6.24 – ≤ 6.6.*
- unaffected 6.7.12 – ≤ 6.7.*
- unaffected 6.8.3 – ≤ 6.8.*
- unaffected 6.9 – ≤ *
References
References4
- https://git.kernel.org/stable/c/0427c8ef8bbb7f304de42ef51d69c960e165e052 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/3a25878a3378adce5d846300c9570f15aa7f7a80 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/2885d54af2c2e1d910e20d5c8045bae40e02fbc1 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/ef1e68236b9153c27cb7cf29ead0c532870d4215 (opens in a new tab)x_transferred
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-2024-35791 (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
[](https://cveledger.app/cve/CVE-2024-35798)Record last updated .