MediaTek Modem Firmware DoS via Error Handling Crash
CVE-2026-20420 Published on February 2, 2026
In Modem, there is a possible system crash due to incorrect error handling. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01738313; Issue ID: MSV-5935.
Vulnerability Analysis
Weakness Type
Out-of-bounds Read
The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.
Products Associated with CVE-2026-20420
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Affected Versions
MediaTek, Inc. MediaTek chipset:- Version MT2735 is affected.
- Version MT2737 is affected.
- Version MT6813 is affected.
- Version MT6815 is affected.
- Version MT6833 is affected.
- Version MT6835 is affected.
- Version MT6853 is affected.
- Version MT6855 is affected.
- Version MT6858 is affected.
- Version MT6873 is affected.
- Version MT6875 is affected.
- Version MT6877 is affected.
- Version MT6878 is affected.
- Version MT6879 is affected.
- Version MT6880 is affected.
- Version MT6883 is affected.
- Version MT6885 is affected.
- Version MT6886 is affected.
- Version MT6889 is affected.
- Version MT6890 is affected.
- Version MT6891 is affected.
- Version MT6893 is affected.
- Version MT6895 is affected.
- Version MT6896 is affected.
- Version MT6897 is affected.
- Version MT6899 is affected.
- Version MT6980 is affected.
- Version MT6983 is affected.
- Version MT6985 is affected.
- Version MT6986 is affected.
- Version MT6989 is affected.
- Version MT6990 is affected.
- Version MT6991 is affected.
- Version MT6993 is affected.
- Version MT8676 is affected.
- Version MT8791 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.