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CVE Record

CVE-2021-35133: Use after free in the synx driver issue while performing other functions during multiple invocation of synx...

Use after free in the synx driver issue while performing other functions during multiple invocation of synx release calls in Snapdragon Connectivity, Snapdragon Industrial IOT, Snapdragon Mobile

MediumCVSS 6.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Qualcomm Snapdragon driver memory-safety bug. An attacker who already has high local privileges on an affected device could abuse repeated synx release behavior to compromise confidentiality, integrity, or availability. The business risk is highest for mobile, IoT, and embedded fleets using affected Snapdragon components.

Executive priority

Treat this as a moderate-priority firmware risk. It is not evidenced as actively exploited, but affected Snapdragon devices may sit in long-lived mobile, IoT, or operational environments where firmware remediation is slow.

Technical view

CVE-2021-35133 is a use-after-free in Qualcomm's synx driver during multiple synx release invocations. CVSS 3.1 is 6.7 with local attack vector, low complexity, high privileges required, no user interaction, unchanged scope, and high confidentiality, integrity, and availability impact.

Likely exposure

Exposure depends on devices shipping the affected Qualcomm Snapdragon Connectivity, Industrial IoT, or Mobile components listed by Qualcomm and the CVE record. Asset owners may need OEM, carrier, or embedded-vendor firmware details because end products often mask the underlying chipset.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation. The CVSS vector indicates exploitation requires local access and high privileges, which reduces broad remote risk but matters after device compromise or on managed embedded systems.

Researcher notes

Evidence is limited to the CVE metadata and Qualcomm bulletin reference. No CWE is listed in the bundle. The key technical facts are use-after-free, synx driver, repeated release calls, local access, high privileges, and high CIA impact in CVSS.

Mitigation direction

  • Check Qualcomm's July 2022 security bulletin for vendor guidance.
  • Request patched firmware status from device OEMs, carriers, or embedded suppliers.
  • Prioritize affected mobile, IoT, and embedded devices with privileged local users.
  • Track firmware rollout completion for production and fielded devices.
  • Monitor Qualcomm and OEM advisories for updated remediation details.

Validation and detection

  • Inventory devices and modules using affected Qualcomm Snapdragon components.
  • Map device firmware or security patch levels to OEM remediation guidance.
  • Confirm whether products include the Qualcomm synx driver path.
  • Review procurement BOMs or SBOMs for listed QCA, WCN, WCD, SD, or SM parts.
  • Document exceptions where OEM patch status is unavailable.
Prepared
Confidence
medium
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

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CVE-2021-35133 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.7 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6.7CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H0.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.7Medium
CVSS 3.1 vector shape for CVE-2021-35133Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Qualcomm, Inc.Snapdragon Connectivity, Snapdragon Industrial IOT, Snapdragon MobileAR8035, QCA6174A, QCA6391, QCA8081, QCA8337, QCA9377, QCM6490, QCS6490, SD 8 Gen1 5G, SD480, SD780G, SD888 5G, SDX12, SDX65, SM7450, SM8475, SM8475P, WCD9335, WCD9341, WCD9370, WCD9375, WCD9380, WCD9385, WCN3988, WCN3991, WCN6740, WCN6750, WCN6850, WCN6851, WCN6855, WCN6856, WCN7850, WCN7851, WSA8830, WSA8832, WSA8835Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.