CVE-2021-35108
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 · uneditedImproper checking of AP-S lock bit while verifying the secure resource group permissions can lead to non secure read and write access in Snapdragon Connectivity, 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 confidenceThe vulnerability involves improper validation of the AP-S (Application Processor-Secure) lock bit during secure resource group permission checks in Qualcomm Snapdragon chipsets. This allows untrusted non-secure code to bypass security boundaries and perform read/write operations on protected secure resources. The flaw effectively compromises the trusted execution environment by failing to properly enforce the lock mechanism that should isolate secure from non-secure domains.
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
- Physical
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:P/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 modelCheck the device or system documentation, boot logs, or system information to determine the exact Qualcomm chipset (Sd 8 Gen1 5g, Sm7450, Sm8475, Sm8475p, Wcd9370, Wcd9375, Wcd9380, or Wcd9385)Affected if The chipset matches one of the affected models listed in the CVE
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Verify firmware versionRetrieve the firmware version for the identified chipset component (Application Processor firmware or WCD audio codec firmware) using device manufacturer tools, system logs, or firmware dump utilitiesAffected if The firmware version corresponds to any version of the affected chipsets (all versions are affected per the CVE)
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Check secure boot statusInspect the secure boot configuration or trust zone settings through device diagnostics, boot logs, or manufacturer-provided secure status toolsAffected if Secure boot verification is disabled, misconfigured, or reports as unverified
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Verify AP-S lock bit handlingThis requires low-level access to the trusted execution environment or secure processor diagnostics to inspect whether the AP-S lock bit is properly enforced during secure resource group permission checksAffected if The AP-S lock bit validation is found to be bypassed or improperly enforced, allowing non-secure code access to secure resources
The environment is affected if the device uses any of the listed Qualcomm chipsets (Sd 8 Gen1 5g, Sm7450, Sm8475, Sm8475p, Wcd9370, Wcd9375, Wcd9380, Wcd9385) and has not received the vendor firmware patch addressing the AP-S lock bit validation flaw.
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 vendor-supplied firmware patch from Qualcomm and ensure device manufacturers have integrated the updated secure boot/permission verification components. End users should update their devices to receive the patched firmware.
- Consultation8.0 h
- Implementation4.0 h
- Testing16.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,856.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-35108 — 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-2021-35108 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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