CVE-2021-1975
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 heap overflow due to improper length check of domain while parsing the DNS response in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon 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 heap buffer overflow vulnerability exists in the DNS response parsing code of affected Snapdragon chipsets. The vulnerability stems from improper length validation when processing domain names in DNS responses, allowing an attacker to overflow a heap-allocated buffer with controlled data by sending a specially crafted DNS response.
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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 chipset modelUse commands like 'lspci', 'cat /proc/cpuinfo', or check device documentation to determine the exact Qualcomm chipset model. Look for Apq8009, Apq8009w, Apq8017, Apq8037, Apq8096au, Ar6003, Ar8035, or Csr6030 identifiers.Affected if The chipset matches one of the listed models (Apq8009, Apq8009w, Apq8017, Apq8037, Apq8096au, Ar6003, Ar8035, or Csr6030)
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Check firmware versionQuery the device or system firmware version using vendor-specific tools, bootloader information, or system information utilities. For embedded devices, check /proc/version, dmesg, or manufacturer diagnostic interfaces.Affected if Any firmware version is present on an affected chipset (all versions of listed chipsets are vulnerable)
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Verify DNS processing is enabledExamine the device network configuration to determine if DNS response parsing is active. Check for DNS resolver services, network interfaces accepting DNS traffic, or IoT devices with network connectivity that process domain name responses.Affected if The device processes or parses DNS responses on any network interface
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Assess network exposureReview firewall rules, networkACLs, and device network binding to determine if the DNS parsing component can receive responses from untrusted networks. Check if DNS traffic traverses untrusted or attacker-controlled network segments.Affected if The device can receive DNS responses from untrusted network sources
If the device uses one of the affected Qualcomm chipsets (Apq8009, Apq8009w, Apq8017, Apq8037, Apq8096au, Ar6003, Ar8035, or Csr6030) and processes DNS responses from network sources, the environment is affected by CVE-2021-1975.
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 and device manufacturers that address CVE-2021-1975. Until patches are available, minimize exposure by preventing untrusted networks from intercepting DNS traffic.
- Consultation8.0 h
- Implementation40.0 h
- Testing24.0 h
- Review / QA16.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1975 — 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-2021-1975 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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