{"id":"GHSA-9wx9-5pv9-3349","revision":"0447f3b92e8e45659d668dc901aa82f8","records":[{"revision":"0447f3b92e8e45659d668dc901aa82f8","observedAt":"2026-10-28T21:55:29.474+00:00","statement":{"source":"osv","id":"GHSA-9wx9-5pv9-3349","aliases":["CVE-2026-116582"],"title":"Seroval: Script injection through RegExp sources in serialized output","description":"### Summary\n\nseroval writes a `RegExp` as a regular expression literal. In affected versions, the `<` character in a `RegExp` source is written without escaping. A source built from untrusted input can then end the HTML `<script>` element that the serialized output is placed in, and run script in the page.\n\n### Details\n\nseroval escapes `<` in strings, so string values cannot end a `<script>` element. `RegExp` sources did not get the same escaping:\n\n- Versions before 1.0.0 wrote the source as is.\n- Version 1.5.5 stopped escaping `<` in `RegExp` sources, so that named groups and lookbehinds keep working. This removed the escaping for every `<` in a source.\n\nThese functions are affected:\n\n- `serialize`, `serializeAsync`\n- `crossSerialize`, `crossSerializeAsync`, `crossSerializeStream`\n- the `Serializer` class\n- `compileJSON`\n\n`toJSON`, `fromJSON`, `toCrossJSON` and `fromCrossJSON` are not affected, because they never produce JavaScript.\n\n### Impact\n\nAn application is affected when all of these are true:\n\n1. It builds a `RegExp` from untrusted input that is used as regular expression syntax. Input passed through an escaping helper (such as an `escapeRegExp` function) is not enough to exploit this.\n2. It serializes that `RegExp` with one of the functions above.\n3. It places the output inside an HTML `<script>` element, as server rendering usually does.\n\nIn that case an attacker can run script in the page of any user who receives that output.\n\n### Patches\n\nFixed in 1.6.10. A `RegExp` whose source contains `<` is now written with the `RegExp` constructor and an escaped string source. Named groups and lookbehinds keep working.\n\n### Workarounds\n\nIf you cannot upgrade:\n\n- Do not serialize a `RegExp` built from untrusted pattern syntax. Send its source and flags as strings, and build the `RegExp` on the client.\n- Or reject patterns that contain `<` before they reach the serializer.","state":0,"publishedAt":"2026-10-28T21:17:31+00:00","modifiedAt":"2026-10-28T21:30:04.9924147+00:00","affected":[{"ecosystem":"npm","name":"seroval","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"1.5.5"},{"kind":"fixed","version":"1.6.10"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"npm","name":"seroval","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"1.0.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-9wx9-5pv9-3349","https://nvd.nist.gov/vuln/detail/CVE-2026-116582","https://github.com/lxsmnsyc/seroval/commit/f94ee0b63936dae954ff50d5b5e8ea7cb9b284e6","https://github.com/lxsmnsyc/seroval","https://github.com/lxsmnsyc/seroval/releases/tag/seroval@1.6.10"],"sourceUrl":"https://github.com/advisories/GHSA-9wx9-5pv9-3349","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-9wx9-5pv9-3349","identifiers":["GHSA-9wx9-5pv9-3349","CVE-2026-116582"]},"retained":false,"historicalAffected":[]}],"coverage":[]}