CVE-2021-30326
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 · uneditedPossible assertion due to improper size validation while processing the DownlinkPreemption IE in an RRC Reconfiguration/RRC Setup message in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Industrial IOT, 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 · high confidenceImproper size validation in processing the DownlinkPreemption IE within RRC Reconfiguration/RRC Setup messages in Qualcomm Snapdragon chipsets can cause an assertion failure, leading to potential denial of service via specially crafted radio messages.
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 the Qualcomm chipset model in your deviceCheck device hardware specifications, baseband firmware information, or system logs for the chipset identifier. On Linux, you may find this in /proc/cpuinfo or via AT commands (AT+CGMM or AT+QCFG="nw").Affected if The chipset model matches Ar8035, Qca6390, Qca6391, Qca6426, Qca6436, Qca6574a, Qca6574au, or Qca6595au
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Confirm the firmware version is presentRetrieve the baseband or radio firmware version using manufacturer diagnostic tools, firmware dump utilities, or AT commands such as AT+CGMR. This information is typically displayed in system information or modem diagnostic screens.Affected if A firmware version is returned (any version indicates the chipset is present)
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Verify the device processes RRC messagesThis is implicit for any device using the affected chipset for cellular communication. No active check required - the vulnerability exists in the RRC message parser regardless of configuration.Affected if The device uses the chipset for 3GPP cellular communication (4G/5G)
If your device contains any of the listed Qualcomm chipset models (Ar8035, Qca6390, Qca6391, Qca6426, Qca6436, Qca6574a, Qca6574au, Qca6595au) with any firmware version, your environment 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 firmware updates from Qualcomm and device manufacturers; prioritize mobile devices and base station equipment using affected Snapdragon variants.
- Consultation8.0 h
- Implementation2.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,728.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30326 — 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-2021-30326 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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- 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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