CVE-2026-93599 rustls-webpki before 0.103.13 Panic via empty BIT STRING

rustls-webpki through 0.103.12 and 0.104.0-alpha releases before 0.104.0-alpha.7 contains a reachable panic in bitstringflags in src/der.rs. The input guard fails to reject a named-bit BIT STRING whose content is exactly 0x00 zero padding bits and no data bytes, so rawbits.len - 1 underflows on t...