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CVE Record

CVE-2021-35111: Improper validation of tag id while RRC sending tag id to MAC can lead to TOCTOU race condition in Snapdrag...

Improper validation of tag id while RRC sending tag id to MAC can lead to TOCTOU race condition in Snapdragon Connectivity, Snapdragon Mobile

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-35111 is a Qualcomm Snapdragon connectivity/mobile flaw that can cause denial of service. The issue is in validation of a tag ID passed between radio/network stack components, creating a race condition. Business impact is service disruption on affected devices, not confirmed data theft or code execution from the provided sources.

Executive priority

Treat this as a high-priority firmware exposure for affected Qualcomm-based devices, especially where outages disrupt operations. Urgency depends on asset presence and update availability, not on confirmed exploitation.

Technical view

Qualcomm describes improper tag ID validation while RRC sends a tag ID to MAC, leading to a TOCTOU race condition. The CVSS 3.1 vector is network-accessible, low complexity, unauthenticated, no user interaction, unchanged scope, with high availability impact only.

Likely exposure

Exposure is likely where products contain the listed Snapdragon Connectivity or Snapdragon Mobile components and have not received the relevant Qualcomm/OEM firmware update. The source bundle lists many affected chipsets, including QCA, SD, SDX, SM, WCN, WCD, and WSA families.

Exploitation context

The provided bundle says this CVE is not in CISA KEV, and no cited source states active exploitation. Public details are limited to the vendor description and CVSS metadata; do not assume exploit availability.

Researcher notes

The public description is sparse. Focus analysis on affected component inventory, firmware provenance, OEM patch mapping, and availability impact. Avoid inferring confidentiality or integrity risk because the provided CVSS vector marks both as none.

Mitigation direction

  • Check Qualcomm’s June 2022 security bulletin for vendor guidance.
  • Apply OEM firmware or security updates that address CVE-2021-35111.
  • Prioritize internet-connected, managed, or business-critical affected devices.
  • Track carrier or device-manufacturer advisories for update availability.
  • Document exceptions where vendor updates are unavailable.

Validation and detection

  • Inventory devices and modules using the affected Qualcomm parts.
  • Map firmware versions against Qualcomm and OEM June 2022 guidance.
  • Confirm whether affected devices remain supported by the OEM.
  • Verify deployed updates through MDM, asset tools, or vendor diagnostics.
  • Monitor availability incidents on affected device fleets.
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-2021-35111 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
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2021-35111Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 MobileAR8035, QCA6390, QCA6391, QCA8081, QCA8337, SD 8 Gen1 5G, SD765, SD765G, SD768G, SD778G, SD865 5G, SD870, SD888 5G, SDX55, SDX55M, SDX65, SM7250P, SM7450, SM8475, SM8475P, WCD9341, WCD9370, WCD9375, WCD9380, WCD9385, WCN3991, WCN3998, WCN6750, WCN6850, WCN6851, WCN6855, WCN6856, WCN7851, WSA8810, WSA8815, 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.