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CVE Record

CVE-2021-47252: batman-adv: Avoid WARN_ON timing related checks

In the Linux kernel, the following vulnerability has been resolved: batman-adv: Avoid WARN_ON timing related checks The soft/batadv interface for a queued OGM can be changed during the time the OGM was queued for transmission and when the OGM is actually transmitted by the worker. But WARN_ON must be used to denote kernel bugs and not to print simple warnings. A warning can simply be printed using pr_warn.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue affects batman-adv mesh networking. A timing race can trigger a kernel warning when a queued routing message is sent after its interface changed. The source describes a code-quality and stability fix, not data theft or remote code execution.

Executive priority

Treat this as routine kernel hygiene unless batman-adv is operationally important in your environment. Patch through normal maintenance, with higher priority for mesh-networking infrastructure or systems configured to react strongly to kernel warnings.

Technical view

In batman-adv, an Originator Message can be queued on one soft interface and transmitted later after that interface context changes. The fix replaces WARN_ON-based timing checks with pr_warn, because WARN_ON is for kernel bugs and can have stronger operational consequences than a simple warning.

Likely exposure

Exposure is mainly Linux systems running affected kernels with batman-adv enabled or in use for mesh networking. Systems not using the batman-adv module or feature are unlikely to have practical exposure based on the provided sources.

Exploitation context

The bundle does not show CISA KEV listing, public exploitation, exploit code, or a CVSS score. It describes a resolved kernel behavior issue caused by timing, with limited evidence of attacker-controlled impact.

Researcher notes

Evidence is narrow: the record identifies Linux kernel batman-adv timing behavior and stable kernel fixes, but provides no CVSS, CWE, exploitability analysis, or attacker prerequisites. Avoid overstating impact beyond warning behavior and potential operational stability concerns.

Mitigation direction

  • Inventory Linux hosts for batman-adv use or loaded modules.
  • Apply vendor kernel updates containing the referenced stable fixes.
  • Check distribution advisories for exact fixed package versions.
  • Prioritize exposed mesh-networking nodes over unrelated servers.

Validation and detection

  • Confirm current kernel version and distribution patch level.
  • Verify whether batman-adv is enabled, loaded, or required.
  • Map installed kernels against vendor fixed versions or stable commits.
  • Review kernel logs for related batman-adv warning events.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2021-47252 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
9Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxef0a937f7a1450d3a133ccd83c9c7d07587e7a00, ef0a937f7a1450d3a133ccd83c9c7d07587e7a00, ef0a937f7a1450d3a133ccd83c9c7d07587e7a00, ef0a937f7a1450d3a133ccd83c9c7d07587e7a00, ef0a937f7a1450d3a133ccd83c9c7d07587e7a00, ef0a937f7a1450d3a133ccd83c9c7d07587e7a00, ef0a937f7a1450d3a133ccd83c9c7d07587e7a00, ef0a937f7a1450d3a133ccd83c9c7d07587e7a00unaffected
LinuxLinux3.14, 0, 4.4.293, 4.9.274, 4.14.238, 4.19.196, 5.4.128, 5.10.46, 5.12.13, 5.13affected
Weakness

CWE details

No CWE listed

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