musl is a “libc”, an implementation of the standard library functionality described in the ISO C and POSIX standards, plus common extensions, intended for use on Linux-based systems.
A vulnerability was discovered in musl’s tre_tnfa_run_parallel function buffer overflow logic, due to the incorrect use of integer types and missing overflow checks.
An attacker, who controls the regular expression and/or string being searched, could execute arbitrary code with the privileges of the process.
There is no known workaround at this time.
All musl users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-libs/musl-1.1.15-r2"