CVE-2026-23223
Description
A use-after-free flaw was found in the Linux kernel's XFS filesystem scrub functionality. In xchk_btree_check_block_owner(), the code dereferences bs->cur to check if it aliases with bs->sc->sa.bno_cur or bs->sc->sa.rmap_cur after these cursors may have already been freed. This incorrect temporal ordering was introduced when the xfs_btnum_t type was removed, potentially leading to a use-after-free condition during filesystem consistency checks.
Statement
This flaw occurs in the XFS online filesystem scrub code path, which is typically invoked via the xfs_scrub utility with elevated privileges. The race window is narrow and requires specific scrub operations on XFS filesystems. Systems not using XFS or not running filesystem scrub operations are unaffected.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 7.8 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | High | N/A |
| Integrity Impact | None | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The main problem is that -- if a lock is overcome -- data could be altered in a bad state.
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