9.8

CVE-2026-74480: net: bridge: stop fast-leave after deleting a port group

Received
AliasesRHSA-2026:61973RHSA-2026:62345RHSA-2026:62372
Published 15-08-2026Last modified 16-10-2026

Vulnerability summary

CVE-2026-74480 is a critical (CVSS 9.8) vulnerability in linux. EPSS estimates a 0.58% chance of exploitation in the next 30 days, higher than 47.7% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.8 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.58%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 34 · Related 24
OPENSUSE-SU-2026:22091-1RHSA-2026:62346RHSA-2026:62508RHSA-2026:62522RHSA-2026:62568RHSA-2026:62609

Timeline

  1. 15-08-2026
    PublishedVulnerability first disclosed.
  2. 16-10-2026
    Last modifiedVulnerability information updated.

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 metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.58%

Chance of exploitation in the next 30 days

Percentile

48%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.58% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu168 products
  • linuxAll versions (No fix recorded) | < 5.15.0-198.208
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Redhat29 products
  • bpftool< 0:4.18.0-372.211.1.el8_6 | < 0:4.18.0-477.164.1.el8_8 | < 0:4.18.0-305.204.1.el8_4 | < 0:3.10.0-1160.160.1.el7
  • bpftool-debuginfo< 0:4.18.0-372.211.1.el8_6 | < 0:4.18.0-477.164.1.el8_8 | < 0:4.18.0-305.204.1.el8_4 | < 0:3.10.0-1160.160.1.el7
  • kernel< 0:4.18.0-372.211.1.el8_6 | < 0:4.18.0-477.164.1.el8_8 | < 0:4.18.0-305.204.1.el8_4 | < 0:3.10.0-1160.160.1.el7 | < 0:6.12.0-211.54.1.el10_2
  • kernel-64k< 0:6.12.0-211.54.1.el10_2
  • kernel-64k-core< 0:6.12.0-211.54.1.el10_2
Debian2 products
  • linux< 6.1.187-1 | < 6.12.105-1 | < 7.1.8-1
  • linux-6.12< 6.12.107-1~deb12u1
Linux1 product
  • linux≥ 6db6f0eae6052b70885562e1733896647ec1d807, < d6c32e2e25a9a06ba021030e26b6d602a277eb72 | ≥ 6db6f0eae6052b70885562e1733896647ec1d807, < 482bcb85139addb4e8ac8ed10baeda3e0aad4031 | ≥ 6db6f0eae6052b70885562e1733896647ec1d807, < 1a109cc9890d017c41d77e6c82da739579c49f0b | ≥ 6db6f0eae6052b70885562e1733896647ec1d807, < 159ad90cb929c033308bb39a2c5f8fbf393b77aa | ≥ 6db6f0eae6052b70885562e1733896647ec1d807, < 4695430e8132420bf8de94da3eb36a6cf35fde6b | ≥ 6db6f0eae6052b70885562e1733896647ec1d807, < 0309ebbc570000ea0df11c06b69798e5860c5f6f | ≥ 6db6f0eae6052b70885562e1733896647ec1d807, < 4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4 | ≥ 6db6f0eae6052b70885562e1733896647ec1d807, < a39789f211b8a4125f0c70e05b30cf715f4f187d | 4.11

4 vendors · 200 products · Showing 200 of 276

References

36 links
Show all 36 references