Bug 2511397 (CVE-2026-71224) - CVE-2026-71224 gfs2-utils: gfs2-utils: stack overflow via alloca(i_height) in metadata walk
Summary: CVE-2026-71224 gfs2-utils: gfs2-utils: stack overflow via alloca(i_height) in...
Keywords:
Status: NEW
Alias: CVE-2026-71224
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2527996
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-05 08:39 UTC by OSIDB Bzimport
Modified: 2026-09-03 11:58 UTC (History)
3 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-08-05 08:39:42 UTC
A flaw was found in gfs2-utils. The metadata walk code in metawalk.c uses alloca((height + 1) * sizeof(*metalist)) where height is the i_height field from the on-disk inode (uint16, max 65535, valid range 0-10). No bounds validation is performed before the alloca call. An attacker can craft a GFS2 filesystem image with a large i_height value to cause excessive stack allocation (~1MB for i_height=65535 with sizeof(osi_list_t)=16), leading to stack exhaustion and a denial of service (SIGSEGV). The metadata walk in metawalk.c involves recursive traversal, and each level could invoke this alloca, compounding the stack usage. The Linux kernel GFS2 driver validates i_height against sd_max_height in gfs2_dinode_in() and stores it as u8, but the userspace gfs2-utils performs no equivalent validation.


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