EEF-CVE-2026-49760

Stack Buffer Overflow in ei_s_print_term at Very Large Integer

## Summary Stack-based Buffer Overflow vulnerability in Erlang OTP (erl_interface) allows Stack-based Buffer Overflow. This vulnerability is associated with program file `lib/erl_interface/src/misc/ei_printterm.c` and program routine `ei_s_print_term`. The C function `ei_s_print_term` uses an internal 2000-character stack buffer to format terms. When called with an encoded Erlang term containing a very large integer (encoded representation exceeding 2000 characters), the buffer overflows. The overflow bytes are restricted to the ASCII values of `0`-`9` and `A`-`F`, which limits exploitation to Denial of Service. The companion function `ei_print_term`, which prints directly to a `FILE` instead of a memory buffer, does not contain this bug. This issue affects OTP from OTP 17.0 before OTP 27.3.4.13, OTP 28.5.0.2, and OTP 29.0.2, corresponding to erl_interface from 3.7.16 before 5.5.2.1, 5.7.0.1, and 5.8.1. Whether OTP before OTP 17.0, corresponding to erl_interface before 3.7.16, is affected is unknown. ## Workarounds Avoid calling `ei_s_print_term` with untrusted data whose encoded integer representation could exceed 2000 characters.