CVE-2026-71221
Description
A stack out-of-bounds write vulnerability was found in gfs2-utils. In savemeta, the height value from on-disk inode metadata is used as a loop bound without bounds checking, causing a stack buffer overflow that may lead to arbitrary code execution when processing crafted GFS2 filesystem images.
Statement
This vulnerability is assessed as Moderate impact because the unchecked height field enables a stack buffer overflow in savemeta, similar to the di_height OOB write in gfs2_edit. The attacker can overwrite stack memory beyond the fixed-size array, potentially achieving code execution. While RHEL compiler hardening provides partial mitigation, the controlled out-of-bounds write makes exploitation plausible. Exploitation requires local access and user interaction (an administrator must run savemeta on the crafted image). The vulnerability does not affect the kernel GFS2 driver, which validates i_height.
Mitigation
Do not run gfs2-utils savemeta on untrusted or potentially compromised GFS2 filesystem images. Run gfs2-utils tools in a containerized or VM-isolated environment when processing untrusted images. Disable automatic fsck at boot for GFS2 filesystems until patches are applied by setting fs_passno to 0 in /etc/fstab.
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 | N/A | 7 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Acknowledgements
Red Hat would like to thank Tristan Madani (Talence Security) for reporting this issue.
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