CVE-2021-39635

VoLTE disclosure and call control via missing authorization

Published Feb 11, 2022 · Updated Aug 4, 2024

Missing authorization in UNISOC ims_ex on Android SoCs allows local users to access VoLTE data and manage calls without phone permissions. The vendor system service accepts caller requests without checking authorization before exposing sensitive VoLTE information or call-control operations. A normal installed app can reach the service with no phone permission, and the reported impact is limited to VoLTE data access and call management.

CVSS severityUnavailable
Unscored
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in UNISOC ims_ex on Android SoCs allows local users to access VoLTE data and manage calls without phone permissions. The vendor system service accepts caller requests without checking authorization before exposing sensitive VoLTE information or call-control operations. A normal installed app can reach the service with no phone permission, and the reported impact is limited to VoLTE data access and call management.

The record

CVE
CVE-2021-39635
Published
Feb 11, 2022
Updated
Aug 4, 2024
Vendor
UNISOC
Product
ims_ex
Classifications
CWE-862, T1068
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Android SoC

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

UNISOC · ims_exversion=Android SoC

Published CVSS scores

7.3UNISOCCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:L/E:F/RC:C

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

Weakness, pattern, technique

CWE-862Missing Authorization
T1068Exploitation for Privilege Escalation

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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