CVE-2026-21367
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedTransient DOS when processing nonstandard FILS Discovery Frames with out-of-range action sizes during initial scans.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA transient denial-of-service vulnerability exists in Wi-Fi implementations when processing nonstandard FILS (Fast Initial Link Setup) Discovery Frames with out-of-range action sizes during initial scans. The vulnerability stems from insufficient validation of action size fields in FILS Discovery Frames, allowing malformed frames to cause service disruption.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Wi-Fi hardware and firmware versionCheck the network interface or system information to determine the Wi-Fi chipset and firmware version. On Linux, this can be done using 'lspci' for PCIe Wi-Fi cards, 'lsusb' for USB adapters, or by checking the driver information via 'ethtool -i' or 'iw dev'. Look for Qualcomm brand chipsets matching the affected models: Ar8035, Cologne, Csr8811, Fastconnect 6200, 6700, 6900, 7800, or Fwa Gen 3 Ultra.Affected if The system uses any of the listed Qualcomm firmware products (Ar8035, Cologne, Csr8811, Fastconnect 6200/6700/6900/7800, Fwa Gen 3 Ultra) regardless of version.
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Determine if FILS (Fast Initial Link Setup) is enabledCheck the Wi-Fi interface configuration for FILS support and activation. On Linux, use 'iw list' to see supported authentication suites and FILS capabilities, or check the interface configuration via 'iw dev <interface> info'. Look for FILS-related settings in hostapd configuration files if the device acts as an access point.Affected if FILS is enabled and the interface is configured to process FILS Discovery Frames.
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Verify Wi-Fi interface is in a scanning stateMonitor the Wi-Fi interface for active scanning behavior, as the vulnerability triggers during initial scans. Use 'iw dev <interface> scan' to trigger a scan and observe the interface status. On Linux, check interface state via 'ip link show' or 'iw dev <interface> link' to confirm the interface is active and capable of receiving/processing discovery frames.Affected if The Wi-Fi interface is active and performing or capable of performing initial scans that would process FILS Discovery Frames.
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Inspect system logs for Wi-Fi disruptionsReview system and kernel logs for Wi-Fi-related errors, disconnections, or service disruptions that may indicate exploitation. Check 'dmesg', 'journalctl', or '/var/log/syslog' for Wi-Fi driver messages, especially those mentioning FILS, discovery frames, or firmware crashes.Affected if Logs show unexplained Wi-Fi service disruptions, firmware crashes, or error messages related to FILS Discovery Frame processing.
A system is affected if it uses any of the listed Qualcomm firmware products with FILS enabled and the Wi-Fi interface is active for scanning operations, as the vulnerability triggers during initial scans with malformed FILS Discovery Frames.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement strict bounds checking and validation of action size fields in FILS Discovery Frame processing logic; apply vendor firmware or software updates when available.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-21367 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-21367 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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