{"id":"CVE-2026-55618","aliases":["GHSA-fxgq-9m89-cxj9","PYSEC-2026-3831"],"url":"https://o3.security/vulnerability/CVE-2026-55618","summary":"eml_parser: URL extraction bypass via HTML entities in URLs","details":"## Summary\n\n`eml_parser` performs certain validations on potential URL strings to discard bogus values. In versions prior to `3.0.2`, this validation was performed before unescaping any HTML entities that might occur in the string. This caused the library to wrongfully reject valid URLs that use HTML entities for the `:`, `/`, or `.` characters. These URLs would then not be included in the list of extracted URLs. Similarly, the host parts of such URLs would not be extracted.\n\nFor example, neither the URL `https://phishing.example.com` nor its host (`phishing.example.com`) would appear in the parsing result.\n\n## Impact\n\n`eml_parser` is used in email security gateways and SOC pipelines to extract URLs as IOCs. Those URLs are then checked against threat-intel feeds, URL reputation services, and sandboxes. A URL that is not extracted is never checked.\n\n## Patches\n\nSince version 3.0.2 the library unescapes all HTML entities in every URL before deciding to accept or reject it. A test was added to prevent regressions.","published":"2026-08-25T18:21:56.178Z","modified":"2026-09-11T03:30:41.221915877Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"eml-parser","fixedVersion":"3.0.2"}],"fix":{"url":"https://github.com/GOVCERT-LU/eml_parser/commit/746a69f86443eb0b6a47f77db3cfe727c21f92b3","label":"GOVCERT-LU/eml_parser@746a69f"},"references":[{"type":"WEB","url":"https://github.com/GOVCERT-LU/eml_parser/releases/tag/v3.0.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55618.json"},{"type":"ADVISORY","url":"https://github.com/GOVCERT-LU/eml_parser/security/advisories/GHSA-fxgq-9m89-cxj9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55618"},{"type":"FIX","url":"https://github.com/GOVCERT-LU/eml_parser/commit/746a69f86443eb0b6a47f77db3cfe727c21f92b3"},{"type":"FIX","url":"https://github.com/GOVCERT-LU/eml_parser/pull/90"},{"type":"PACKAGE","url":"https://github.com/GOVCERT-LU/eml_parser"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-11T03:30:41.221915877Z"}}