CVE-2022-48733

Advisory lineage Upstream: 0 Downstream: 20
Modified
Published: 20 Jun 2024, 11:13
Last modified:11 May 2026, 18:45

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (nvd)
EPSS Score
0.01% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

20 Jun 2024, 11:13
Published
Vulnerability first disclosed
11 May 2026, 18:45
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 2%

Techniques & Countermeasures

  • CWE-416•Use After Free

    The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected Systems

  • linux•linux

    ≥ c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2, < 7e4c72dbaf62f8978af8321a24dbd35566d3a78a | ≥ c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2, < a7b717fa15165d3d9245614680bebc48a52ac05d | ≥ c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2, < 9372fa1d73da5f1673921e365d0cd2c27ec7adc2 | ≥ c37b2b6269ee4637fb7cdb5da0d1e47215d57ce2, < 28b21c558a3753171097193b6f6602a94169093a | 3.7

  • linux•linux_kernel

    < 5.10.226 | ≥ 5.11, < 5.15.22 | ≥ 5.16, < 5.16.8 | 5.17:rc1 | 5.17:rc2

References (5)