CVE-2021-35121

Memory corruption via improper mutex array indexing

Published Jun 14, 2022 · Updated Aug 4, 2024

Improper array-index validation in the Synx driver for Qualcomm Snapdragon platforms allows local users to trigger use-after-free memory corruption. The driver uses an inadequately validated array index to select mutexes for locking and unlocking, allowing a freed object to be accessed. Reaching the flaw requires high local privileges; Qualcomm describes no demonstrated post-corruption outcome beyond the use-after-free condition.

CVSS severity6.7
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper array-index validation in the Synx driver for Qualcomm Snapdragon platforms allows local users to trigger use-after-free memory corruption. The driver uses an inadequately validated array index to select mutexes for locking and unlocking, allowing a freed object to be accessed. Reaching the flaw requires high local privileges; Qualcomm describes no demonstrated post-corruption outcome beyond the use-after-free condition.

The record

CVE
CVE-2021-35121
Published
Jun 14, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-129
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jun 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.7Qualcomm, Inc.CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-129Improper Validation of Array Index

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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