RIOT 2020.04 has a buffer overflow in the base64 decoder. The decoding function base64_decode() uses an output buffer estimation function to compute the required buffer capacity and validate against the provided buffer size. The base64_estimate_decode_size() function calculates the expected decoded size with an arithmetic round-off error and does not take into account possible padding bytes. Due to this underestimation, it may be possible to craft base64 input that causes a buffer overflow.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15350
Reference (s):
- https://drive.google.com/file/d/1jMCAi8uawV1-an5uCghIxT2TEdxCE1Lk/view?usp=sharing
- https://github.com/RIOT-OS/RIOT/pull/14400