CVE-2021-35111
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 · uneditedImproper validation of tag id while RRC sending tag id to MAC can lead to TOCTOU race condition in Snapdragon Connectivity, Snapdragon Mobile
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 TOCTOU race condition exists in the RRC (Radio Resource Control) layer of Qualcomm Snapdragon chipsets where improper validation of tag id during communication between RRC and MAC allows potential exploitation. The vulnerability exists in Snapdragon Connectivity and Snapdragon Mobile components used in mobile devices.
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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:H/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 device chipset modelCheck the device system information or FCC certification documents to determine the specific Qualcomm chipset or Wi-Fi/ modem firmware version in use. On Android, this may appear in Settings > About Phone > Baseband or through AT commands (AT+GMR).Affected if The chipset or firmware matches any of these: Ar8035, Qca6390, Qca6391, Qca8081, Qca8337, SD 8 Gen1 5G, SD765, or SD765g.
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Confirm firmware versionRetrieve the current firmware version string from the device's radio firmware or baseband information. On Android devices, use *#*#4636#*#* or a hardware info app to view baseband version.Affected if The firmware version string contains any of the affected identifiers (Ar8035, Qca6390, Qca6391, Qca8081, Qca8337, SD8Gen1, SD765, or SD765g).
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Verify RRC layer is activeConfirm the device uses an active cellular radio connection. The vulnerability exists in the RRC (Radio Resource Control) layer which handles communication between the device and cell tower. This layer is engaged whenever the device has cellular connectivity.Affected if The device maintains any cellular network connection (2G, 3G, 4G, or 5G) using the affected Qualcomm chipset.
If the device contains any of the listed Qualcomm firmware components (Ar8035, Qca6390, Qca6391, Qca8081, Qca8337, SD 8 Gen1 5G, SD765, or SD765g) and uses cellular connectivity, the device is affected by this vulnerability.
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 dataApply vendor-supplied firmware updates from Qualcomm/ device OEMs. This is a firmware-level issue requiring patched radio firmware; no application-level mitigations are available.
- Consultation1.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-35111 — 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-2021-35111 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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