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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 39/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.57% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 0309ebbc570000ea0df11c06b69798e5860c5f6f, 159ad90cb929c033308bb39a2c5f8fbf393b77aa, 1a109cc9890d017c41d77e6c82da739579c49f0b; azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 6.6.152.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0309ebbc570000ea0df11c06b69798e5860c5f6f, 159ad90cb929c033308bb39a2c5f8fbf393b77aa, 1a109cc9890d017c41d77e6c82da739579c49f0b; azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 6.6.152.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Aug 15, 2026
Updated
Oct 16, 2026
EPSS
0.5% · 47th percentile
CWE
—

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.11affected
    • 6db6f0eae6052b70885562e1733896647ec1d807 and later · before d6c32e2e25a9a06ba021030e26b6d602a277eb72affected · git
    • 6db6f0eae6052b70885562e1733896647ec1d807 and later · before 482bcb85139addb4e8ac8ed10baeda3e0aad4031affected · git
    • 6db6f0eae6052b70885562e1733896647ec1d807 and later · before 1a109cc9890d017c41d77e6c82da739579c49f0baffected · git
    • 6db6f0eae6052b70885562e1733896647ec1d807 and later · before 159ad90cb929c033308bb39a2c5f8fbf393b77aaaffected · git
    • 6db6f0eae6052b70885562e1733896647ec1d807 and later · before 4695430e8132420bf8de94da3eb36a6cf35fde6baffected · git
    • 6db6f0eae6052b70885562e1733896647ec1d807 and later · before 0309ebbc570000ea0df11c06b69798e5860c5f6faffected · git
    • 6db6f0eae6052b70885562e1733896647ec1d807 and later · before 4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4affected · git
    • 6db6f0eae6052b70885562e1733896647ec1d807 and later · before a39789f211b8a4125f0c70e05b30cf715f4f187daffected · git
    • before 4.11not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.54.1.el10_26.12.0-211.54.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-74476Aug 15, 2026 · veth: convert frag_list skbs before running XDP
    36Monitor
  • ← EarlierCVE-2026-74479Aug 15, 2026 · net: pktgen: fix proc entry use-after-free
    31Monitor
  • Later →CVE-2026-74481Aug 15, 2026 · mm/page_reporting: use system_freezable_wq to fix UAF during suspend
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0309ebbc570000ea0df11c06b69798e5860c5f6fVendor (CNA)
Linux Linux159ad90cb929c033308bb39a2c5f8fbf393b77aaVendor (CNA)
Linux Linux1a109cc9890d017c41d77e6c82da739579c49f0bVendor (CNA)
Linux Linux4695430e8132420bf8de94da3eb36a6cf35fde6bVendor (CNA)
Linux Linux482bcb85139addb4e8ac8ed10baeda3e0aad4031Vendor (CNA)
Linux Linux4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4Vendor (CNA)
Linux Linuxa39789f211b8a4125f0c70e05b30cf715f4f187dVendor (CNA)
Linux Linuxd6c32e2e25a9a06ba021030e26b6d602a277eb72Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.06.6.152.1-1 · Release NotesMicrosoft (MSRC)
almalinux:bpftool4.18.0-553.160.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.160.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-core4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-core4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-devel4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-modules4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-modules-extra4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-devel4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-modules4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-modules-extra4.18.0-553.160.1.rt7.501.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.107-1~deb12u1 · Debian:12Package registry (OSV)
red hat:bpftool0:4.18.0-372.211.1.el8_6 · Red Hat:rhel_aus:8.6::baseosPackage registry (OSV)
red hat:bpftool-debuginfo0:4.18.0-372.211.1.el8_6 · Red Hat:rhel_aus:8.6::baseosPackage registry (OSV)
red hat:kernel0:4.18.0-372.211.1.el8_6 · Red Hat:rhel_aus:8.6::baseosPackage registry (OSV)
red hat:kernel-abi-stablelists0:4.18.0-372.211.1.el8_6 · Red Hat:rhel_aus:8.6::baseosPackage registry (OSV)
red hat:kernel-core0:4.18.0-372.211.1.el8_6 · Red Hat:rhel_aus:8.6::baseosPackage registry (OSV)
red hat:kernel-debug0:4.18.0-372.211.1.el8_6 · Red Hat:rhel_aus:8.6::baseosPackage registry (OSV)
red hat:kernel-debug-core0:4.18.0-372.211.1.el8_6 · Red Hat:rhel_aus:8.6::baseosPackage registry (OSV)

+7

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records