CVE-2021-30300
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 denial of service due to incorrectly decoding hex data for the SIB2 OTA message and assigning a garbage value to choice when processing the SRS configuration in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Voice & Music, Snapdragon Wearables
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 confidenceA denial of service vulnerability exists in Qualcomm Snapdragon baseband firmware where incorrectly decoded hex data in the SIB2 OTA (System Information Block 2 Over-The-Air) message causes a garbage value to be assigned to a choice variable during SRS (Sounding Reference Signal) configuration processing. This memory corruption or invalid state assignment can cause the device to crash or become unresponsive.
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 device chipset modelCheck the device specifications or use AT commands (like 'AT+GMR' or 'AT+CGMM' for Qualcomm modems) to query the modem chipset/model numberAffected if The chipset matches Apq8009w, Apq8017, Apq8096au, Ar8035, Csrb31024, Fsm10055, Fsm10056, or Mdm8207
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Confirm firmware versionQuery the baseband firmware version using vendor-specific AT commands (such as 'AT+QLFVER' or through the device's engineering mode), or check the modem firmware information in the device's about/settings pagesAffected if Any firmware version is installed on an affected chipset - all versions are vulnerable
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Verify cellular network connectivityThe vulnerability triggers during SIB2 OTA message processing during normal cellular operation. Check if the device has active LTE/5G connectivity by examining network statusAffected if Device has cellular capability and connects to a mobile network - the flaw activates when processing SIB2 messages from the network
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Check for OEM firmware updatesContact the device OEM or check the manufacturer support website for available firmware/security patches for this specific device modelAffected if No firmware update addressing CVE-2021-30300 has been applied by the OEM
If the device uses any of the affected Qualcomm chipset models (Apq8009w, Apq8017, Apq8096au, Ar8035, Csrb31024, Fsm10055, Fsm10056, Mdm8207) and processes cellular network signals without the corresponding security patch, the device is vulnerable to denial of service via malformed SIB2 OTA messages.
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 the Qualcomm firmware/security patch (CVE-2021-30300) from the device OEM. Users should check for and apply available firmware updates for affected Snapdragon devices.
- Consultation8.0 h
- Implementation24.0 h
- Testing16.0 h
- Review / QA8.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30300 — 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-2021-30300 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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