CVE-2022-48733
btrfs: fix use-after-free after failure to create a snapshot
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free after failure to create a snapshot At ioctl.c:create_snapshot(), we allocate a pending snapshot structure and then attach it to the transaction's list of pending snapshots. After that we call btrfs_commit_transaction(), and if that returns an error we jump to 'fail' label, where we kfree() the pending snapshot structure. This can result in a later use-after-free of the pending snapshot: 1) We allocated the pending snapshot and added it to the transaction's list of pending snapshots; 2) We call btrfs_commit_transaction(), and it fails either at the first call to btrfs_run_delayed_refs() or btrfs_start_dirty_block_groups(). In both cases, we don't abort the transaction and we release our transaction handle. We jump to the 'fail' label and free the pending snapshot structure. We return with the pending snapshot still in the transaction's list; 3) Another task commits the transaction. This time there's no error at all, and then during the transaction commit it accesses a pointer to the pending snapshot structure that the snapshot creation task has already freed, resulting in a user-after-free. This issue could actually be detected by smatch, which produced the following warning: fs/btrfs/ioctl.c:843 create_snapshot() warn: '&pending_snapshot->list' not removed from list So fix this by not having the snapshot creation ioctl directly add the pending snapshot to the transaction's list. Instead add the pending snapshot to the transaction handle, and then at btrfs_commit_transaction() we add the snapshot to the list only when we can guarantee that any error returned after that point will result in a transaction abort, in which case the ioctl code can safely free the pending snapshot and no one can access it anymore.
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 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.23% · top 86% of all CVEs (6 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.
Weakness
Affected products
- affected c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2 – < 7e4c72dbaf62f8978af8321a24dbd35566d3a78a
- affected c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2 – < a7b717fa15165d3d9245614680bebc48a52ac05d
- affected c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2 – < 9372fa1d73da5f1673921e365d0cd2c27ec7adc2
- affected c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2 – < 28b21c558a3753171097193b6f6602a94169093a
- affected 3.7
- unaffected < 3.7
- unaffected 5.10.226 – ≤ 5.10.*
- unaffected 5.15.22 – ≤ 5.15.*
- unaffected 5.16.8 – ≤ 5.16.*
- unaffected 5.17 – ≤ *
References (5)
- https://git.kernel.org/stable/c/7e4c72dbaf62f8978af8321a24dbd35566d3a78a (opens in a new tab)
- https://git.kernel.org/stable/c/a7b717fa15165d3d9245614680bebc48a52ac05d (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/9372fa1d73da5f1673921e365d0cd2c27ec7adc2 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/28b21c558a3753171097193b6f6602a94169093a (opens in a new tab)x_transferred
- https://lists.debian.org/debian-lts-announce/2024/10/msg00003.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)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2022-48733)Record last updated .