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. MT2735, MT2737, MT6813, MT6815, MT6833, MT6835, MT6853, MT6855, MT6858, MT6873, MT6875, MT6877, MT6878, MT6879, MT6880, MT6883, MT6885, MT6886, MT6889, MT6890, MT6891, MT6893, MT6895, MT6896, MT6897, MT6899, MT6980, MT6983, MT6985, MT6986, MT6989, MT6990, MT6991, MT6993, MT8676, MT8791 Version Modem NR15, NR16, NR17, NR17R is affected by CVE-2026-20420Exploit 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.