Linux Kernel up to 7.2-rc5 Bridge br_multicast_leave_group use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k0.50-

Summaryinfo

A vulnerability described as very critical has been identified in Linux Kernel up to 6.6.150/6.12.102/6.18.43/7.1.7/7.2-rc5. This affects the function br_multicast_leave_group of the component Bridge. Such manipulation leads to use after free. This vulnerability is traded as CVE-2026-74480. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.150/6.12.102/6.18.43/7.1.7/7.2-rc5 and classified as very critical. Affected by this issue is the function br_multicast_leave_group of the component Bridge. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-74480 since 08/15/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 6.6.151, 6.12.103, 6.18.44, 7.1.8 or 7.2-rc6 eliminates this vulnerability. Applying the patch 159ad90cb929c033308bb39a2c5f8fbf393b77aa/4695430e8132420bf8de94da3eb36a6cf35fde6b/0309ebbc570000ea0df11c06b69798e5860c5f6f/4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4/a39789f211b8a4125f0c70e05b30cf715f4f187d is able to eliminate this problem.

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Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.151/6.12.103/6.18.44/7.1.8/7.2-rc6
Patch: 159ad90cb929c033308bb39a2c5f8fbf393b77aa/4695430e8132420bf8de94da3eb36a6cf35fde6b/0309ebbc570000ea0df11c06b69798e5860c5f6f/4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4/a39789f211b8a4125f0c70e05b30cf715f4f187d

Timelineinfo

08/15/2026 Advisory disclosed
08/15/2026 +0 days CVE reserved
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74480 (🔒)
GCVE (CVE): GCVE-0-2026-74480
GCVE (VulDB): GCVE-100-390794

Entryinfo

Created: 08/15/2026 15:12
Changes: 08/15/2026 15:12 (59)
Complete: 🔍
Cache ID: 216::103

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