Critical severity · published Aug 15, 2026
CVE-2026-74480
net: bridge: stop fast-leave after deleting a port group
9.8
CVSS
0.6%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
net: bridge: stop fast-leave after deleting a port group
br_multicast_leave_group() iterates mp->ports with pp = &p->next in
its fast-leave path. After br_multicast_del_pg() removes p,
continuing the loop advances pp through the deleted entry.
If multicast-to-unicast was enabled, the bridge can hold multiple port
groups for the same port and group with different source MAC
addresses. Once multicast-to-unicast is disabled,
br_port_group_equal() matches those entries by port only. A fast leave
can then delete one entry and continue from its stale next pointer,
leaving mp->ports pointing at a deleted port group.
Fast leave only needs to remove one matching port group. Break after
br_multicast_del_pg() so the loop stops before dereferencing the
removed entry.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 47% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
6db6f0eae6052b70885562e1733896647ec1d807 before d6c32e2e25a9a06ba021030e26b6d602a277eb72; 6db6f0eae6052b70885562e1733896647ec1d807 before 482bcb85139addb4e8ac8ed10baeda3e0aad4031; 6db6f0eae6052b70885562e1733896647ec1d807 before 1a109cc9890d017c41d77e6c82da739579c49f0b; 6db6f0eae6052b70885562e1733896647ec1d807 before 159ad90cb929c033308bb39a2c5f8fbf393b77aa; 6db6f0eae6052b70885562e1733896647ec1d807 before 4695430e8132420bf8de94da3eb36a6cf35fde6b; 6db6f0eae6052b70885562e1733896647ec1d807 before 0309ebbc570000ea0df11c06b69798e5860c5f6f; +3 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-74480
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-74480
git.kernel.org
https://git.kernel.org/stable/c/0309ebbc570000ea0df11c06b69798e5860c5f6f
git.kernel.org
https://git.kernel.org/stable/c/159ad90cb929c033308bb39a2c5f8fbf393b77aa
git.kernel.org
https://git.kernel.org/stable/c/1a109cc9890d017c41d77e6c82da739579c49f0b
git.kernel.org
https://git.kernel.org/stable/c/4695430e8132420bf8de94da3eb36a6cf35fde6b
git.kernel.org
https://git.kernel.org/stable/c/482bcb85139addb4e8ac8ed10baeda3e0aad4031
git.kernel.org
https://git.kernel.org/stable/c/4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4
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