{"id":"CVE-2026-93990","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-93990","summary":"Expat through 2.8.4 fails to validate low surrogates following high surrogates in UTF-16 input, allowing malformed UTF-16 sequences to be accepted. Attackers can craft UTF-16 encoded…","details":"Expat through 2.8.4 fails to validate low surrogates following high surrogates in UTF-16 input, allowing malformed UTF-16 sequences to be accepted. Attackers can craft UTF-16 encoded XML with lone high surrogates that consume following code units, hiding markup characters from the parser and enabling XML injection attacks.","published":"2026-09-19T23:17:10.203","modified":"2026-09-19T23:17:10.203","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/libexpat/libexpat/commit/ff6e1d7e750bbe245178f51a47a965dc8342861a","label":"libexpat/libexpat@ff6e1d7"},"references":[{"type":"WEB","url":"https://github.com/libexpat/libexpat"},{"type":"WEB","url":"https://github.com/libexpat/libexpat/commit/ff6e1d7e750bbe245178f51a47a965dc8342861a"},{"type":"WEB","url":"https://github.com/libexpat/libexpat/pull/1282"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/expat-through-2.8.4-malformed-utf-16-acceptance-via-unchecked-surrogate"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-09-19T23:17:10.203"}}