Remote privilege escalation via unchecked modem write
Published Mar 2, 2026 · Updated Mar 2, 2026
Out-of-bounds write in MediaTek Modem LR12A, LR13, NR15, NR16, and NR17 allows remote attackers to escalate privileges. The Modem subcomponent writes beyond an intended buffer because a bounds check is missing; MediaTek has not disclosed the affected code path or input field. Exploitation requires a UE to connect to an attacker-controlled rogue base station and requires user interaction, with successful exploitation elevating execution privileges in the modem.
Summary
What happened
Out-of-bounds write in MediaTek Modem LR12A, LR13, NR15, NR16, and NR17 allows remote attackers to escalate privileges. The Modem subcomponent writes beyond an intended buffer because a bounds check is missing; MediaTek has not disclosed the affected code path or input field. Exploitation requires a UE to connect to an attacker-controlled rogue base station and requires user interaction, with successful exploitation elevating execution privileges in the modem.
The record
- CVE
- CVE-2026-20434
- Published
- Mar 2, 2026
- Updated
- Mar 2, 2026
- Vendor
- MediaTek
- Product
- MediaTek Modem
- Classifications
- CWE-787, T1404
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 2, 2026CVE publishedPublication date reported by the CVE source.
- Mar 2, 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.
- Affected versionversion=Modem LR12A, LR13, NR15, NR16, NR17
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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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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