CVE-2026-20461

UE crash via unchecked modem write

Published Jul 1, 2026 · Updated Jul 1, 2026

Out-of-bounds write in the MediaTek Chipset modem allows physically proximate attackers to crash a UE through a rogue base station. The modem omits a bounds check before writing data derived from base-station traffic outside the intended buffer; MediaTek has not disclosed the affected routine or message. Exploitation requires the UE to connect to an attacker-controlled base station, requires no privileges or user interaction, and affects availability only.

CVSS severity5.3
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in the MediaTek Chipset modem allows physically proximate attackers to crash a UE through a rogue base station. The modem omits a bounds check before writing data derived from base-station traffic outside the intended buffer; MediaTek has not disclosed the affected routine or message. Exploitation requires the UE to connect to an attacker-controlled base station, requires no privileges or user interaction, and affects availability only.

The record

CVE
CVE-2026-20461
Published
Jul 1, 2026
Updated
Jul 1, 2026
Vendor
MediaTek
Product
MediaTek Chipset
Classifications
CWE-787, T1642
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 1, 2026Record 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=MT2737
  2. Affected versionversion=MT6813
  3. Affected versionversion=MT6835
  4. Affected versionversion=MT6858
  5. Affected versionversion=MT6878
  6. Affected versionversion=MT6879
  7. Affected versionversion=MT6886
  8. Affected versionversion=MT6895
  9. Affected versionversion=MT6896
  10. Affected versionversion=MT6897
  11. Affected versionversion=MT6899
  12. Affected versionversion=MT6980
  13. Affected versionversion=MT6983
  14. Affected versionversion=MT6985
  15. Affected versionversion=MT6988
  16. Affected versionversion=MT6989
  17. Affected versionversion=MT6990
  18. Affected versionversion=MT6991
  19. Affected versionversion=MT6993
  20. Affected versionversion=MT8673
  21. Affected versionversion=MT8676
  22. Affected versionversion=MT8678
  23. Affected versionversion=MT8755
  24. Affected versionversion=MT8775
  25. Affected versionversion=MT8792
  26. Affected versionversion=MT8793
  27. Affected versionversion=MT8795T
  28. Affected versionversion=MT8796
  29. Affected versionversion=MT8798
  30. Affected versionversion=MT8863
  31. Affected versionversion=MT8873
  32. Affected versionversion=MT8883
  33. Affected versionversion=MT8893

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

MediaTek · MediaTek Chipsetversion=MT2737; version=MT6813; version=MT6835; version=MT6858; version=MT6878; version=MT6879; version=MT6886; version=MT6895; version=MT6896; version=MT6897; version=MT6899; version=MT6980; version=MT6983; version=MT6985; version=MT6988; version=MT6989; version=MT6990; version=MT6991; version=MT6993; version=MT8673; version=MT8676; version=MT8678; version=MT8755; version=MT8775; version=MT8792; version=MT8793; version=MT8795T; version=MT8796; version=MT8798; version=MT8863; version=MT8873; version=MT8883; version=MT8893

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:A/AC:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
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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