Description
HTML::Entities versions before 3.84 for Perl read freed heap memory in _decode_entities. The XS routine backing HTML::Entities::_decode_entities cached a pointer (repl) into the entity-value SV returned by hv_fetch on the entity2char hash. When the input SV was identical to a value SV in that hash, and that value contained its own key as an entity reference, a later call to grow_gap() reallocated the SV's PV buffer and freed the backing allocation that repl still pointed into. The subsequent copy loop read repl_len bytes from the freed allocation. The read may disclose adjacent heap contents into the destination SV.
Problem types
Product status
Any version before 3.84
Timeline
| 2026-05-12: | Issue reported. |
| 2026-05-19: | HTML-Parser 3.84 released. |
References
www.openwall.com/lists/oss-security/2026/06/04/2
github.com/libwww-perl/HTML-Parser/pull/56
github.com/...6922552b0778c90a9587a3894e248be4d3a25e1c.patch