CVE-2021-35111Network attack vector

Remote service interruption via modem tag race

Published Jun 14, 2022 · Updated Aug 4, 2024

TOCTOU race in the modem of Qualcomm Snapdragon Connectivity and Snapdragon Mobile allows remote attackers to interrupt device service. The RRC layer inadequately validates a tag identifier before sending it to the MAC layer, allowing the identifier's state to change between validation and use. No privileges or user interaction are required; successful exploitation affects availability without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

TOCTOU race in the modem of Qualcomm Snapdragon Connectivity and Snapdragon Mobile allows remote attackers to interrupt device service. The RRC layer inadequately validates a tag identifier before sending it to the MAC layer, allowing the identifier's state to change between validation and use. No privileges or user interaction are required; successful exploitation affects availability without reported data disclosure or modification.

The record

CVE
CVE-2021-35111
Published
Jun 14, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-367, T1499
Attack vector
network
Privileges
unauthenticated

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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5Qualcomm, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1499Endpoint Denial of Service

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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