Remote system crash via unchecked modem input
Published Sep 7, 2026 · Updated Sep 7, 2026
Reachable assertion in the MediaTek Chipset modem allows remote attackers to crash the system through a rogue base station. The modem processes attacker-controlled base-station input without a required bounds check, allowing an out-of-range condition to reach an assertion. Exploitation requires the UE to connect to the attacker-controlled station, but requires no privileges or user interaction and interrupts device service.
Summary
What happened
Reachable assertion in the MediaTek Chipset modem allows remote attackers to crash the system through a rogue base station. The modem processes attacker-controlled base-station input without a required bounds check, allowing an out-of-range condition to reach an assertion. Exploitation requires the UE to connect to the attacker-controlled station, but requires no privileges or user interaction and interrupts device service.
The record
- CVE
- CVE-2026-20504
- Published
- Sep 7, 2026
- Updated
- Sep 7, 2026
- Vendor
- MediaTek
- Product
- MediaTek Chipset
- Classifications
- CWE-617, T1499
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 7, 2026CVE publishedPublication date reported by the CVE source.
- Sep 7, 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=MT2735
- Affected versionversion=MT6833
- Affected versionversion=MT6853
- Affected versionversion=MT6855
- Affected versionversion=MT6873
- Affected versionversion=MT6875
- Affected versionversion=MT6877
- Affected versionversion=MT6880
- Affected versionversion=MT6883
- Affected versionversion=MT6885
- Affected versionversion=MT6889
- Affected versionversion=MT6890
- Affected versionversion=MT6891
- Affected versionversion=MT6893
- Affected versionversion=MT8675
- Affected versionversion=MT8771
- Affected versionversion=MT8791
- Affected versionversion=MT8791T
- Affected versionversion=MT8797
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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.
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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