A CVE-type vulnerability in musl libc's crypt function causes a sentinel value "*" (returned for overly long passwords) to collide with Unix's locked-account indicator, potentially granting unauthenticated shell access on musl-based systems like Alpine without PAM. The article uses this bug to argue that C's lack of proper error-handling types enables dangerous in-band signaling that better-typed languages like Rust would prevent.
Background
Musl libc is a lightweight C standard library commonly used in Alpine Linux. The crypt() function hashes passwords per POSIX spec but must signal errors somehow when it cannot compute a hash.
- Source
- Lobsters
- Published
- Nov 8, 2026 at 05:05 AM
- Score
- 7.0 / 10