CVE-2021-30339
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 · uneditedReading PRNG output may lead to improper key generation due to lack of buffer validation in Snapdragon Connectivity, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Wearables, Snapdragon Wired Infrastructure and Networking
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 confidenceThis vulnerability in Qualcomm Snapdragon chips involves improper buffer validation when reading Pseudo Random Number Generator (PRNG) output, which can lead to weak or predictable key generation. The lack of proper bounds checking when accessing PRNG output allows improper key material to be generated, potentially compromising cryptographic operations.
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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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 affected Qualcomm chips in your environmentInventory network devices, WiFi adapters, IoT devices, or embedded systems using Qualcomm Snapdragon, Ar8035, Qca6391, Qca8081, Qca8337, Qca9984, Qcm2290, Qcm4290, or Qcm6490 chips. Check device datasheets, hardware manifests, or component BOMs.Affected if Any of these specific Qualcomm chip models are present in your environment
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Determine firmware version of affected chipsAccess device management interfaces (e.g., switch CLI, router admin panel, IoT device settings) and locate firmware version information for the Qualcomm component. Commands like 'show version' on network gear or system info pages on IoT devices may reveal version strings.Affected if The firmware version cannot be determined or is older than available patched releases from Qualcomm
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Verify if PRNG is used for cryptographic key generationReview cryptographic implementation documentation or code that relies on the Qualcomm chip's PRNG output. Check whether keys for TLS, VPN, authentication, or other crypto operations are derived from the affected PRNG subsystem.Affected if Cryptographic keys are generated using PRNG output from the affected Qualcomm chip
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Check for vendor security advisoriesSearch Qualcomm advisory database or your device vendor's security bulletin for CVE-2021-30339 and confirm whether your specific chip/firmware combination is listed as affected.Affected if Your device vendor has not issued a firmware update addressing CVE-2021-30339 for your chip model
If you have any of the listed Qualcomm chips (Ar8035, Qca6391, Qca8081, Qca8337, Qca9984, Qcm2290, Qcm4290, Qcm6490) and use them for cryptographic operations involving PRNG output, your environment is affected.
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 Qualcomm firmware/security updates for affected Snapdragon products; verify that cryptographic key generation uses properly validated PRNG output with adequate buffer checks.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30339 — 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-2021-30339 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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