Medium [CVE-2026-71219] Gfs2-utils: gfs2-utils: stack overflow via alloca(1<<di_depth) in hash table traversal
This medium-severity Red Hat Linux advisory covers CVE-2026-71219 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 hash table traversal code in metawalk.c uses alloca() with an exponentially-derived size from the untrusted on-disk di_depth field without bounds validation.
A crafted GFS2 filesystem image with a large di_depth value causes stack exhaustion and a denial of service when processed by fsck.gfs2, gfs2_edit, or savemeta. This vulnerability is assessed as Moderate impact because the alloca-based stack exhaustion results in a process crash (SIGSEGV) rather than controlled memory corruption.
Exploitation requires local access and user interaction: an administrator must run a gfs2-utils tool (fsck.gfs2, gfs2_edit, or savemeta) on a crafted GFS2 filesystem image. The vulnerability does not affect the kernel GFS2 driver, which validates di_depth in gfs2_dinode_in().
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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