Medium [CVE-2026-71224] Gfs2-utils: gfs2-utils: stack overflow via alloca(i_height) in metadata walk
This medium-severity Red Hat Linux advisory covers CVE-2026-71224 affecting Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9.
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Summary
A stack overflow vulnerability was found in gfs2-utils. The metadata walk code in metawalk.c uses alloca() with an untrusted inode height value from on-disk metadata without bounds validation, causing stack exhaustion and a denial of service when processing crafted GFS2 filesystem images.
This vulnerability is assessed as Moderate impact because the alloca-based stack exhaustion results in a process crash (SIGSEGV) rather than controlled memory corruption. RHEL stack guard pages prevent the overflow from reaching other memory regions, confining the impact to denial of service.
Exploitation requires local access and user interaction (an administrator must run fsck.gfs2 or other gfs2-utils tools on a crafted GFS2 filesystem image). The vulnerability does not affect the kernel GFS2 driver, which validates i_height against sd_max_height.
Red Hat severity: Moderate — CVSS 4.7 (CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H). Weakness: CWE-770.
Affected Red Hat products: Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: gfs2-utils.src.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- Run gfs2-utils tools in a containerized or VM-isolated environment when processing potentially compromised or untrusted GFS2 filesystem images. Disable automatic fsck at boot for GFS2 filesystems until patches are applied by setting fs_passno to 0 in /etc/fstab. Use ulimit -s to reduce the stack size limit, converting potential exploitation into a controlled crash.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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