Bug 2555049 (CVE-2026-98705)

Summary:	CVE-2026-98705 kernel: wifi: mac80211: account proxy paths against the mesh path limit
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 mac80211 wireless subsystem. When wireless mesh proxy paths are removed or expire, the interface path counter is decremented without having been accounted for during path creation. An attacker can exploit this accounting flaw through rapid proxy path churn, driving the counter down and bypassing the maximum mesh path limit. This failure to enforce path limits can lead to excessive resource consumption and 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 2026-10-18 15:51:35 UTC

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

wifi: mac80211: account proxy paths against the mesh path limit

Proxy-path churn can drive the interface path counter negative and let
later mesh path additions exceed MESH_MAX_MPATHS.

mesh_path_free_rcu() decrements the interface mpaths counter for entries
from both the mesh and proxy path tables, but mpp_path_add() never
reserves a slot in that counter. Removing or expiring a proxy path
therefore returns a slot that was never charged.

mesh_path_add() uses the same counter to enforce MESH_MAX_MPATHS, so once
it falls below the number of installed paths the limit no longer holds.

Reserve the shared quota before allocating a proxy path and release it on
every unsuccessful addition. Mesh and proxy paths now share one
1024-entry budget, so mpp_path_add() can return -ENOSPC at that limit.

Comment 1 Mauro Matteo Cascella 2026-10-22 09:47:57 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98705.mbox