Bug 2559754 (CVE-2026-99031) - CVE-2026-99031 kernel: net: bridge: avoid recursive multicast port cleanup
Summary: CVE-2026-99031 kernel: net: bridge: avoid recursive multicast port cleanup
Keywords:
Status: NEW
Alias: CVE-2026-99031
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-23 13:30 UTC by OSIDB Bzimport
Modified: 2026-10-28 03:48 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-10-23 13:30:46 UTC
In the Linux kernel, the following vulnerability has been resolved:

net: bridge: avoid recursive multicast port cleanup

br_multicast_sg_del_exclude_ports() removes automatically added STAR_EXCL
port groups by calling br_multicast_del_pg(). For S,G entries, that
deletion calls back into br_multicast_sg_del_exclude_ports(), so a large
number of STAR_EXCL ports consumes one kernel stack frame per port and can
hit the stack guard page.

Keep the complete port-group deletion path for cleanup, but suppress the
S,G exclude-port cleanup while that helper is already walking the same
entry. Normal deletion callers retain the existing behavior.


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