CVE-2024-26837

Multicast traffic disruption via duplicate MDB replays

Published Apr 17, 2024 · Updated May 11, 2026

A race condition in affected Linux kernels allows local users to disrupt multicast forwarding through rapid bridge membership changes. The bridge switchdev replay builder walks br->mdb_list while deferred add notifications remain queued, causing drivers to receive the same membership twice. Local privileges, multicast snooping, switchdev offload, and a reference-counting driver such as DSA are required; stale hardware groups can then misroute or drop multicast traffic after bridge replacement.

CVSS severity4.7
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in affected Linux kernels allows local users to disrupt multicast forwarding through rapid bridge membership changes. The bridge switchdev replay builder walks br->mdb_list while deferred add notifications remain queued, causing drivers to receive the same membership twice. Local privileges, multicast snooping, switchdev offload, and a reference-counting driver such as DSA are required; stale hardware groups can then misroute or drop multicast traffic after bridge replacement.

The record

CVE
CVE-2024-26837
Published
Apr 17, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-362
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 17, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=4f2673b3a2b6246729a1ff13b8945a040839dbd3 <2d5b4b3376fa146a23917b8577064906d643925f
  2. Affected versionversion=4f2673b3a2b6246729a1ff13b8945a040839dbd3 <603be95437e7fd85ba694e75918067fb9e7754db
  3. Affected versionversion=4f2673b3a2b6246729a1ff13b8945a040839dbd3 <dc489f86257cab5056e747344f17a164f63bff4b
  4. Affected versionversion=4f2673b3a2b6246729a1ff13b8945a040839dbd3 <e0b4c5b1d760008f1dd18c07c35af0442e54f9c8
  5. Affected versionversion=5.13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4f2673b3a2b6246729a1ff13b8945a040839dbd3 <2d5b4b3376fa146a23917b8577064906d643925f; version=4f2673b3a2b6246729a1ff13b8945a040839dbd3 <603be95437e7fd85ba694e75918067fb9e7754db; version=4f2673b3a2b6246729a1ff13b8945a040839dbd3 <dc489f86257cab5056e747344f17a164f63bff4b; version=4f2673b3a2b6246729a1ff13b8945a040839dbd3 <e0b4c5b1d760008f1dd18c07c35af0442e54f9c8; version=5.13

Published CVSS scores

4.7NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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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