CVE-2021-47252

Service interruption via raced OGM interface switch

Published May 21, 2024 · Updated May 11, 2026

Improper warning handling in Linux before 5.13 allows local users to interrupt service by racing a batman-adv OGM transmission. In batadv_iv_ogm_emit(), a queued OGM whose outgoing interface moved to another soft interface reaches WARN_ON(), treating a timing race as a kernel bug instead of a normal warning. The race requires local privileges to reconfigure a batman-adv interface; with panic_on_warn enabled, the warning panics the kernel, while default handling drops that queued OGM.

CVSS severity5.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper warning handling in Linux before 5.13 allows local users to interrupt service by racing a batman-adv OGM transmission. In batadv_iv_ogm_emit(), a queued OGM whose outgoing interface moved to another soft interface reaches WARN_ON(), treating a timing race as a kernel bug instead of a normal warning. The race requires local privileges to reconfigure a batman-adv interface; with panic_on_warn enabled, the warning panics the kernel, while default handling drops that queued OGM.

The record

CVE
CVE-2021-47252
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 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=3.14
  2. Affected versionversion=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <282baa8104af44e04c4af3e7f933b44267c7f86f
  3. Affected versionversion=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <2eb4e0b3631832a4291c8bf4c9db873f60b128c8
  4. Affected versionversion=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <45011f2973f6b52cf50db397bb27bf805f5f0e7f
  5. Affected versionversion=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <6031daaaf6d5c359c99dfffa102e332df234ff09
  6. Affected versionversion=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <77a99aad5bc3ea105806ebae6be3cbadc2fc615e
  7. Affected versionversion=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <9f460ae31c4435fd022c443a6029352217a16ac1
  8. Affected versionversion=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <e7fbd8184fa9e85f0d648c499841cb7ff6dec9f4
  9. Affected versionversion=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <e8e9d2968a9d08bf5c683afca182f1537edebf8d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.14; version=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <282baa8104af44e04c4af3e7f933b44267c7f86f; version=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <2eb4e0b3631832a4291c8bf4c9db873f60b128c8; version=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <45011f2973f6b52cf50db397bb27bf805f5f0e7f; version=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <6031daaaf6d5c359c99dfffa102e332df234ff09; version=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <77a99aad5bc3ea105806ebae6be3cbadc2fc615e; version=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <9f460ae31c4435fd022c443a6029352217a16ac1; version=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <e7fbd8184fa9e85f0d648c499841cb7ff6dec9f4; version=ef0a937f7a1450d3a133ccd83c9c7d07587e7a00 <e8e9d2968a9d08bf5c683afca182f1537edebf8d

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/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 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

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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