CVE-2026-46159btrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak
- 4.7MediumCVSS base score
- 0.10%Exploitation in 30 daysEPSS · top 99% 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 btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak btrfs_ioctl_space_info() has a TOCTOU race between two passes over the block group RAID type lists. The first pass counts entries to determine the allocation size, then the second pass fills the buffer. The groups_sem rwlock is released between passes, allowing concurrent block group removal to reduce the entry count. When the second pass fills fewer entries than the first pass counted, copy_to_user() copies the full alloc_size bytes including trailing uninitialized kmalloc bytes to userspace. Fix by copying only total_spaces entries (the actually-filled count from the second pass) instead of alloc_size bytes, and switch to kzalloc so any future copy size mismatch cannot leak heap data.
Timeline
ID reserved
By Linux
- 15 days later
· 15 days later
Published
- 5 months later
· 5 months 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 |
|---|---|---|---|
| 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)
- 0.10% · top 99% 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 4.7.
Affected products
- affected 7fde62bffb576d384ea49a3aed3403d5609ee5bc – < f407aad350bdea4db300c47433573b7a41630d33
- affected 7fde62bffb576d384ea49a3aed3403d5609ee5bc – < d8224b1be6627c6c3b204bfb264508d27c65ac44
- affected 7fde62bffb576d384ea49a3aed3403d5609ee5bc – < d69a4a6813fdba7c4cc3695a7e843842b240790d
- affected 7fde62bffb576d384ea49a3aed3403d5609ee5bc – < f5ee467b56764964027c361641f64953fc0f8f9a
- affected 7fde62bffb576d384ea49a3aed3403d5609ee5bc – < 4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3
- affected 7fde62bffb576d384ea49a3aed3403d5609ee5bc – < 5d12e0ab009ade48c1bff9324fd9bea2c773d088
- affected 7fde62bffb576d384ea49a3aed3403d5609ee5bc – < d09d67d5de577cedae3de9497dff217e0ac8b641
- affected 7fde62bffb576d384ea49a3aed3403d5609ee5bc – < 973e57c726c1f8e77259d1c8e519519f1e9aea77
- affected 2.6.34
- unaffected < 2.6.34
- unaffected 5.10.259 – ≤ 5.10.*
- unaffected 5.15.210 – ≤ 5.15.*
- unaffected 6.1.176 – ≤ 6.1.*
- unaffected 6.6.140 – ≤ 6.6.*
- unaffected 6.12.90 – ≤ 6.12.*
- unaffected 6.18.32 – ≤ 6.18.*
- unaffected 7.0.7 – ≤ 7.0.*
- unaffected 7.1 – ≤ *
References
References9
- https://git.kernel.org/stable/c/f407aad350bdea4db300c47433573b7a41630d33 (opens in a new tab)
- https://git.kernel.org/stable/c/d8224b1be6627c6c3b204bfb264508d27c65ac44 (opens in a new tab)
- https://git.kernel.org/stable/c/d69a4a6813fdba7c4cc3695a7e843842b240790d (opens in a new tab)
- https://git.kernel.org/stable/c/f5ee467b56764964027c361641f64953fc0f8f9a (opens in a new tab)
- https://git.kernel.org/stable/c/4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3 (opens in a new tab)
- https://git.kernel.org/stable/c/5d12e0ab009ade48c1bff9324fd9bea2c773d088 (opens in a new tab)
- https://git.kernel.org/stable/c/d09d67d5de577cedae3de9497dff217e0ac8b641 (opens in a new tab)
- https://git.kernel.org/stable/c/973e57c726c1f8e77259d1c8e519519f1e9aea77 (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)
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-2026-32786 (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-2026-46159)Record last updated .