Bug 2467227 (CVE-2026-43178)

Summary:	CVE-2026-43178 kernel: procfs: fix possible double mmput() in do_procmap_query()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in the Linux kernel's procfs component. A local user, by providing a malformed input buffer during a specific memory mapping query (PROCMAP_QUERY), can trigger an error in how the kernel manages process memory. This can lead to a double release of memory resources, potentially causing the system to crash and resulting in a denial of service (DoS).	Story Points:	---
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Last Closed:		Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-05-06 13:11:54 UTC

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

procfs: fix possible double mmput() in do_procmap_query()

When user provides incorrectly sized buffer for build ID for PROCMAP_QUERY
we return with -ENAMETOOLONG error.  After recent changes this condition
happens later, after we unlocked mmap_lock/per-VMA lock and did mmput(),
so original goto out is now wrong and will double-mmput() mm_struct.  Fix
by jumping further to clean up only vm_file and name_buf.

Comment 1 Keith Grant 2026-05-06 20:12:12 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050638-CVE-2026-43178-3c95@gregkh/T