CVE-2026-72389

bridge: stp: Fix a potential use-after-free when deleting a bridge

State: Published
Severity: 7.8 High
Published: Aug 15, 2026
Updated: Oct 16, 2026
Reserved: Aug 9, 2026

Description

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

bridge: stp: Fix a potential use-after-free when deleting a bridge

The three STP timers are not supposed to be armed while the bridge is administratively down. They are synchronously deactivated when the bridge is put administratively down and the various call sites check for 'IFF_UP' before arming them.

This check is missing from br_topology_change_detection() and it is possible to engineer a situation in which the topology change timer is armed while the bridge is administratively down, resulting in a use-after-free [1] when the bridge is deleted.

Fix by adding the missing check and for good measures synchronously shutdown the three timers when the bridge is deleted.

[1] ODEBUG: free active (active state 0) object: ffff88811662b9b0 object type: timer_list hint: br_topology_change_timer_expired (net/bridge/br_stp_timer.c:120) WARNING: lib/debugobjects.c:629 at debug_print_object+0x1bc/0x450, CPU#9: ip/359

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before c86579b0a2d201792bcb59316629f4ba4758cfc8Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 297a747f59bff6573196d7236178144d66524e68Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 4c40eec06eeac37c58e47a6058eb32901218d5d4Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 39283907a25e5caf0f2bd2947f6e56644b01e2b7Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b4b3458ef88df4798632619f018791d4344bcd92Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 40cbfa3a28e0919469d1b086629bb3ce38a83593Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 2a00517db8de4be7df3d483b215c5544fb30a191Affected
LinuxLinux	2.6.12Affected before 2.6.12Not affected 5.15.212 through 5.15.Not affected 6.1.178 through 6.1.Not affected 6.6.145 through 6.6.Not affected 6.12.97 through 6.12.Not affected 6.18.40 through 6.18.Not affected 7.1.5 through 7.1.Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before c86579b0a2d201792bcb59316629f4ba4758cfc8Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 297a747f59bff6573196d7236178144d66524e68Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 4c40eec06eeac37c58e47a6058eb32901218d5d4Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 39283907a25e5caf0f2bd2947f6e56644b01e2b7Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b4b3458ef88df4798632619f018791d4344bcd92Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 40cbfa3a28e0919469d1b086629bb3ce38a83593Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 2a00517db8de4be7df3d483b215c5544fb30a191Affected

LinuxLinux

2.6.12Affected
before 2.6.12Not affected
5.15.212 through 5.15.*Not affected
6.1.178 through 6.1.*Not affected
6.6.145 through 6.6.*Not affected
6.12.97 through 6.12.*Not affected
6.18.40 through 6.18.*Not affected
7.1.5 through 7.1.*Not affected
7.2 and laterNot affected

References

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