CVE-2026-80530
Description
A flaw was found in the Linux kernel's XFS filesystem. When performing file range exchanges with the XFS_EXCHMAPS_INO1_WRITTEN flag set, the reflink flag can be prematurely cleared from an inode that still manages shared written data. This can lead to data corruption between files that share data through the reflink mechanism, as subsequent writes may bypass Copy-on-Write (CoW) protection.
Statement
XFS exchange-range handling can incorrectly clear the reflink inode flag when XFS_EXCHMAPS_INO1_WRITTEN is used and hole or unwritten mappings from file1 are skipped. As a result, an inode may retain shared written extents while no longer being marked as reflinked. Subsequent writes to that inode can bypass the CoW path and modify the underlying shared blocks in place, thereby altering data visible through other reflink-related files. This is a filesystem integrity and access-control violation, not a kernel memory-corruption primitive.
Mitigation
To mitigate this issue, prevent module xfs from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.
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 | 7.1 | N/A | 7.1 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
An adversary that can cause a resource counter to become inaccurate may be able to create situations where resources are not accounted for and not released, thus causing resources to become scarce for future needs.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An adversary that can cause a resource counter to become inaccurate may be able to force an error that causes the product to crash or exit out of its current operation.
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