CVE-2021-25477Network attack vector

Remote modem crash via ASN.1 double free

Published Oct 6, 2021 · Updated Aug 3, 2024

Double free in the MediaTek RRC stack in Samsung Mobile Devices before SMR Oct-2021 Release 1 allows remote attackers to crash the modem. The LTE RRC decoder frees the same memory twice while handling malformed ASN.1 control data, corrupting modem memory and terminating baseband service. The crafted control message must reach a select device using an MT6762, MT6765, or MT6853 chipset; the documented consequence is a modem service interruption without data disclosure or modification.

CVSS severity4.4
Medium
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

Double free in the MediaTek RRC stack in Samsung Mobile Devices before SMR Oct-2021 Release 1 allows remote attackers to crash the modem. The LTE RRC decoder frees the same memory twice while handling malformed ASN.1 control data, corrupting modem memory and terminating baseband service. The crafted control message must reach a select device using an MT6762, MT6765, or MT6853 chipset; the documented consequence is a modem service interruption without data disclosure or modification.

The record

CVE
CVE-2021-25477
Published
Oct 6, 2021
Updated
Aug 3, 2024
Vendor
Samsung Electronics Co., Ltd.
Product
Samsung Mobile Devices
Classifications
CWE-415, T1642
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=P(9.0), Q(10.0), R(11.0) <SMR Oct-2021 Release 1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Samsung Electronics Co., Ltd. · Samsung Mobile Devicesversion=P(9.0), Q(10.0), R(11.0) <SMR Oct-2021 Release 1

Published CVSS scores

4.4Samsung MobileCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
4.9NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:N/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)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-415Double Free
T1642Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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