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CVE-2026-74480Suited to automated attack · CISA

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

CVSS score

9.8

EPSS probability

%0.6

Risk score

0.1

Published

2 mo ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Official patch verified

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-74480 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

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.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-74480 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1linuxLinux View
2linuxLinux View
Total affected vendors: 1|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
9.8CVSS V3_1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVE CNA
9.8CVSS V31CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HNVD
7.5CVSS 3.x—CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HMicrosoft MSRC

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

reference

Yama veya çözüm referansı

Open source
Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-74480 is associated with the following CWEs:

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CWE-20: Improper Input Validation

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-74480 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

https://git.kernel.org/stable/c/d6c32e2e25a9a06ba021030e26b6d602a277eb72vendor-advisoryhttps://git.kernel.org/stable/c/482bcb85139addb4e8ac8ed10baeda3e0aad4031vendor-advisoryhttps://git.kernel.org/stable/c/1a109cc9890d017c41d77e6c82da739579c49f0bvendor-advisoryhttps://git.kernel.org/stable/c/159ad90cb929c033308bb39a2c5f8fbf393b77aavendor-advisoryhttps://git.kernel.org/stable/c/4695430e8132420bf8de94da3eb36a6cf35fde6bvendor-advisoryhttps://git.kernel.org/stable/c/0309ebbc570000ea0df11c06b69798e5860c5f6fvendor-advisoryhttps://git.kernel.org/stable/c/4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4vendor-advisoryhttps://git.kernel.org/stable/c/a39789f211b8a4125f0c70e05b30cf715f4f187dvendor-advisoryhttps://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgradepatch

CVSS Vector Radar Chart

9.8 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Yama doğrulandı

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

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