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CVE-2026-74480

CRITICALCVSS 9.8/10EPSS 0.46%

Last modified

CVE-2026-74480 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 0.46% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.46%

38.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 6db6f0eae6052b70885562e1733896647ec1d807, < d6c32e2e25a9a06ba021030e26b6d602a277eb72; >= 6db6f0eae6052b70885562e1733896647ec1d807, < 482bcb85139addb4e8ac8ed10baeda3e0aad4031; >= 6db6f0eae6052b70885562e1733896647ec1d807, < 1a109cc9890d017c41d77e6c82da739579c49f0b; >= 6db6f0eae6052b70885562e1733896647ec1d807, < 159ad90cb929c033308bb39a2c5f8fbf393b77aa; >= 6db6f0eae6052b70885562e1733896647ec1d807, < 4695430e8132420bf8de94da3eb36a6cf35fde6b; >= 6db6f0eae6052b70885562e1733896647ec1d807, < 0309ebbc570000ea0df11c06b69798e5860c5f6f; >= 6db6f0eae6052b70885562e1733896647ec1d807, < 4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4; >= 6db6f0eae6052b70885562e1733896647ec1d807, < a39789f211b8a4125f0c70e05b30cf715f4f187d
LinuxLinux4.11

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74480?
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.
How severe is CVE-2026-74480?
CVE-2026-74480 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.46% probability of exploitation in the next 30 days.
How do I fix CVE-2026-74480?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST