Bug 2467208 (CVE-2026-43209)

Summary:	CVE-2026-43209 kernel: minix: Add required sanity checking to minix_check_superblock()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's minix filesystem implementation. The `minix_check_superblock()` function lacks proper sanity checks for superblock fields, including `s_log_zone_size`. This oversight could allow a local attacker to craft a malicious minix filesystem that, when mounted, may lead to a system crash or corruption, resulting in a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-05-06 13:10:54 UTC

In the Linux kernel, the following vulnerability has been resolved:

minix: Add required sanity checking to minix_check_superblock()

The fs/minix implementation of the minix filesystem does not currently
support any other value for s_log_zone_size than 0. This is also the
only value supported in util-linux; see mkfs.minix.c line 511. In
addition, this patch adds some sanity checking for the other minix
superblock fields, and moves the minix_blocks_needed() checks for the
zmap and imap also to minix_check_super_block().

This also closes a related syzbot bug report.

Comment 1 Keith Grant 2026-05-06 21:37:22 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050648-CVE-2026-43209-3ed2@gregkh/T