npm / libmime
libmime
What changed in libmime 5, from its official release notes, upgrade guides and advisories. Sources checked 2026-10-18.
1 security1 new APIs and options2 performance4 fixes and other
See which of these apply to your code, ranked, in your agent:
npx @unstale/cli initlibmime 58 changes
Security 1
Header parsing was hardened against prototype pollution and parser differentials.
New APIs and options 1
Exposes normalizeCharset() on the public API.
Performance 2
Long non-ASCII words are encoded in linear time, improving encoding performance.
Flowed decoding and header unfolding now run in linear time.
Fixes and other changes 4
RFC 2231 parameters are marked as decoded.
Transfer-encoding codecs are refused when used as charsets.
B-encoded words are decoded through libbase64.
charset.decode returns a string for Japanese encodings.