Kernel warning via frame-type-blind length validation
Published May 21, 2024 · Updated May 11, 2026
Improper frame-length validation in the mac80211 scan path allows local users to trigger a cfg80211 kernel warning. The ieee80211_scan_rx function applies hard-coded size thresholds to received probe-response, beacon, and S1G beacon frames instead of deriving each frame type's minimum header length. Reaching the warning requires a crafted frame to enter the wireless scan receive path; the public reproducer demonstrates the warning but does not establish a system crash.
Summary
What happened
Improper frame-length validation in the mac80211 scan path allows local users to trigger a cfg80211 kernel warning. The ieee80211_scan_rx function applies hard-coded size thresholds to received probe-response, beacon, and S1G beacon frames instead of deriving each frame type's minimum header length. Reaching the warning requires a crafted frame to enter the wireless scan receive path; the public reproducer demonstrates the warning but does not establish a system crash.
The record
- CVE
- CVE-2021-47251
- Published
- May 21, 2024
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-1284
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 21, 2024CVE publishedPublication date reported by the CVE source.
- 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.
- Affected versionversion=5.10
- Affected versionversion=cd418ba63f0c2f6157f35a41c9accc6ecb52590a <5a1cd67a801cf5ef989c4783e07b86a25b143126
- Affected versionversion=cd418ba63f0c2f6157f35a41c9accc6ecb52590a <d1b949c70206178b12027f66edc088d40375b5cb
- Affected versionversion=cd418ba63f0c2f6157f35a41c9accc6ecb52590a <e298aa358f0ca658406d524b6639fe389cb6e11e
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- syzbot C reproducer for cfg80211 warningproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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