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Ar8035 FirmwareOperating system · Qualcomm

CVE-2021-35102

HIGH · 7.8 CVSS v3.1 Published 2022-06-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
Zero-click

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 · unedited
Possible buffer overflow due to lack of validation for the length of NAI string read from EFS in Snapdragon Auto, Snapdragon Compute, 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 confidence

A buffer overflow vulnerability exists in Qualcomm Snapdragon chipsets where the length of an NAI (Network Access Identifier) string read from EFS (Embedded File System) is not validated before being copied into a fixed-size buffer. This lack of bounds checking allows an attacker to potentially overflow the buffer by providing an excessively long NAI string.

MitigationApply the vendor-provided firmware update/patch from Qualcomm that adds proper length validation for NAI strings read from EFS. Until then, restrict physical or privileged access to the EFS to prevent manipulation of NAI data.

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 data
Ar8035 FirmwareOperating system
Affected:all versions
Qca6390 FirmwareOperating system
Affected:all versions
Qca6391 FirmwareOperating system
Affected:all versions
Qca6421 FirmwareOperating system
Affected:all versions
Qca6426 FirmwareOperating system
Affected:all versions
Qca6431 FirmwareOperating system
Affected:all versions
Qca6436 FirmwareOperating system
Affected:all versions
Qca6574a FirmwareOperating system
Affected:all versions

CVSS 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
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify chipset model
    Query the device or system information to determine the specific Qualcomm chipset in use (e.g., Ar8035, Qca6390, Qca6391, Qca6421, Qca6426, Qca6431, Qca6436, or Qca6574a). This may be available via hardware identification, bootloader information, or system PCI/network device listings.
    Affected if The device uses any of the listed affected chipsets (Ar8035, Qca6390, Qca6391, Qca6421, Qca6426, Qca6431, Qca6436, or Qca6574a).
  2. Determine EFS access status
    Check whether the Embedded File System (EFS) partition is accessible on the device. This may involve examining mounted filesystems, checking for /efs or similar EFS directories, or reviewing device filesystem permissions and debugging interfaces.
    Affected if EFS is readable or writable by an attacker with physical or privileged access, providing the ability to manipulate NAI data stored there.
  3. Locate NAI configuration
    Search the EFS for NAI-related configuration files or entries. Look for files containing 'NAI', 'Network Access Identifier', or related keywords in the EFS partition or associated configuration directories.
    Affected if An NAI configuration entry exists in EFS, indicating the vulnerable code path may be exercised.
  4. Inspect NAI string length
    If an NAI configuration is found, extract and measure the length of the stored NAI string value. Compare the actual length against the expected fixed buffer size used by the firmware's NAI processing code.
    Affected if The stored NAI string length exceeds the fixed buffer size allocated in the firmware, which would trigger the buffer overflow condition when processed.

A device is affected if it uses any of the listed Qualcomm chipsets, has accessible EFS storage, and contains an NAI string that exceeds the expected buffer length bounds.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor-provided firmware update/patch from Qualcomm that adds proper length validation for NAI strings read from EFS. Until then, restrict physical or privileged access to the EFS to prevent manipulation of NAI data.

Fix this in Ar8035 Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA6.0 h
42.0 hours of engineering $7,360
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-35102 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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