Bug 2527878 (CVE-2026-80755)

Summary:	CVE-2026-80755 kernel: selinux: reject a permission value exceeding the class permission count
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, 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 Security-Enhanced Linux (SELinux) subsystem. This vulnerability occurs because the system does not properly check the size of permission values when processing security policies. A specially crafted SELinux policy could cause the kernel to write data outside of its intended memory area, leading to memory corruption. This could potentially result in a system crash (denial of service) or other unpredictable behavior.	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 2026-09-03 08:43:54 UTC

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

selinux: reject a permission value exceeding the class permission count

perm_read() bounds a permission value by SEL_VEC_MAX but never by the
nprim of the owning class or common, which is taken verbatim from the
policy image.  security_get_permissions() then writes perms[value - 1]
into an nprim-sized kcalloc() array, so a class declaring fewer
permissions than its largest permission value drives an out-of-bounds
heap write.  The top-level symbol tables are validated this way; the
nested per-class permission table is not.

Reject a permission whose value exceeds nprim, which is already set when
perm_read() runs.  Well-formed policies are unaffected.

[PM: tweak comment for line length]

Comment 1 Mauro Matteo Cascella 2026-09-04 08:25:51 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80755.mbox