CVE-2026-74480

Local denial of service via stale port-group pointer

Published Aug 15, 2026 · Updated Aug 15, 2026

Use-after-free in Linux bridge multicast handling allows local users to crash affected systems through a multicast fast leave. br_multicast_leave_group() continues iteration after br_multicast_del_pg() removes an entry, following the deleted entry and leaving mp->ports with a stale pointer. The path requires multicast snooping and a bridge port whose non-default multicast-to-unicast setting was enabled, then disabled, while multicast memberships remained active.

CVSS severity9.8
Critical
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux bridge multicast handling allows local users to crash affected systems through a multicast fast leave. br_multicast_leave_group() continues iteration after br_multicast_del_pg() removes an entry, following the deleted entry and leaving mp->ports with a stale pointer. The path requires multicast snooping and a bridge port whose non-default multicast-to-unicast setting was enabled, then disabled, while multicast memberships remained active.

The record

CVE
CVE-2026-74480
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-825, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.11
  2. Affected versionversion=6db6f0eae6052b70885562e1733896647ec1d807 <0309ebbc570000ea0df11c06b69798e5860c5f6f
  3. Affected versionversion=6db6f0eae6052b70885562e1733896647ec1d807 <159ad90cb929c033308bb39a2c5f8fbf393b77aa
  4. Affected versionversion=6db6f0eae6052b70885562e1733896647ec1d807 <4695430e8132420bf8de94da3eb36a6cf35fde6b
  5. Affected versionversion=6db6f0eae6052b70885562e1733896647ec1d807 <4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4
  6. Affected versionversion=6db6f0eae6052b70885562e1733896647ec1d807 <a39789f211b8a4125f0c70e05b30cf715f4f187d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.11; version=6db6f0eae6052b70885562e1733896647ec1d807 <0309ebbc570000ea0df11c06b69798e5860c5f6f; version=6db6f0eae6052b70885562e1733896647ec1d807 <159ad90cb929c033308bb39a2c5f8fbf393b77aa; version=6db6f0eae6052b70885562e1733896647ec1d807 <4695430e8132420bf8de94da3eb36a6cf35fde6b; version=6db6f0eae6052b70885562e1733896647ec1d807 <4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4; version=6db6f0eae6052b70885562e1733896647ec1d807 <a39789f211b8a4125f0c70e05b30cf715f4f187d

Published CVSS scores

7.8Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.8Linux Kernel CVE TeamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-825Expired Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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