EVerest's Integer Overflow and Signed to Unsigned conversion lead to either stack buffer overflow or infinite loop

Vulnerability Description

EVerest is an EV charging software stack. Prior to version 2025.10.0, an integer overflow occurring in `SdpPacket::parse_header()` allows the current buffer length to be set to 7 after a complete header of size 8 has been read. The remaining length to read is computed using the current length subtracted by the header length which results in a negative value. This value is then interpreted as `SIZE_MAX` (or slightly less) because the expected type of the argument is `size_t`. Depending on whether the server is plain TCP or TLS, this leads to either an infinite loop or a stack buffer overflow. Version 2025.10.0 fixes the issue.

References

• https://github.com/EVerest/everest-core/security/advisories/GHSA-7qq4-q9r8-wc7w