CVE-2021-1981
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 buffer over read due to improper IE size check of Bearer capability IE in MT setup request from network in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, 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 · moderate confidenceBuffer over-read vulnerability in Qualcomm Snapdragon baseband modem firmware where improper size validation of Bearer capability Information Element in Mobile Terminated setup requests from the network allows reading beyond buffer boundaries. This affects multiple Snapdragon product lines including Auto, Compute, Connectivity, Consumer IOT, Industrial IOT, and Mobile chipsets.
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
- High
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 modelCheck the device hardware specifications or use commands like 'lspci', 'lsusb', 'cat /proc/cpuinfo', or check the device's technical documentation to determine the exact Qualcomm chipset or modem model (Apq8017, Ar8035, Msm8917, Qca6390, Qca6391, Qca6421, Qca6426, or Qca6431)Affected if The device uses any of the listed affected chipsets (Apq8017, Ar8035, Msm8917, Qca6390, Qca6391, Qca6421, Qca6426, or Qca6431)
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Check baseband modem firmware versionAccess the baseband modem firmware information through AT commands (e.g., 'AT+CGMR' or 'AT+QVER'), manufacturer diagnostic tools, or firmware dump from the device's modem partitionAffected if The baseband firmware version matches any of the affected products listed (all versions of Apq8017, Ar8035, Msm8917, Qca6390, Qca6391, Qca6421, Qca6426, Qca6431 firmware)
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Verify baseband modem is enabled and activeCheck if the baseband modem functionality is currently active on the device. This can be done by checking modem status via AT commands (e.g., 'AT+CFUN?'), checking running processes related to the modem, or verifying radio/communication interfaces are upAffected if The baseband modem is powered on and actively processing network communications, as the vulnerability triggers when processing Mobile Terminated setup requests from the network
A device is affected if it contains any of the listed Qualcomm chipsets (Apq8017, Ar8035, Msm8917, Qca6390, Qca6391, Qca6421, Qca6426, Qca6431) with the baseband modem enabled and processing network requests, since all firmware versions of these products are vulnerable.
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 patches from Qualcomm; coordinate with device manufacturers for OTA updates. Network-side mitigation is not applicable as the vulnerability is in device firmware processing network messages.
- Consultation8.0 h
- Implementation16.0 h
- Testing24.0 h
- Review / QA12.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $16,384.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1981 — 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-2021-1981 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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