{"id":"CVE-2026-110725","aliases":["GHSA-333x-w4r6-6crp"],"title":"fast-uri vulnerable to scheme injection via an unescaped first-segment colon in suffix references","summary":"fast-uri vulnerable to scheme injection via an unescaped first-segment colon in suffix references","severity":"low","cvss":3.7,"cwe":["CWE-41","CWE-116","CWE-79"],"vendor":"fast-uri","product":"fast-uri","ecosystem":"npm","affected":["fast-uri < 2.4.8","fast-uri >= 3.0.0, < 3.1.9","fast-uri >= 4.0.0, < 4.2.3"],"patched":["fast-uri 2.4.8","fast-uri 3.1.9","fast-uri 4.2.3"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T21:36:41Z","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-333x-w4r6-6crp","references":[{"url":"https://github.com/fastify/fast-uri/security/advisories/GHSA-333x-w4r6-6crp"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-110725"},{"url":"https://github.com/fastify/fast-uri/commit/39e6493c1356f30a0084171627eb266786e1620e"},{"url":"https://github.com/fastify/fast-uri/commit/a9b8d67353630aab053cd727cf629023dd018d2b"},{"url":"https://cna.openjsf.org/security-advisories.html"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v2.4.8"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v3.1.9"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v4.2.3"},{"url":"https://github.com/advisories/GHSA-333x-w4r6-6crp"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-110725.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-110725"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2556007"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-110725"}],"tags":["ghsa","npm","cve.org","csaf","vex","red-hat"],"epss":0.00302,"epssPercentile":0.22817,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-20T19:14:33.067016Z"},"ingestedAt":"2026-10-20T07:55:43.639Z","slug":"CVE-2026-110725","body":"## Overview\n\n### Impact\n\n`fast-uri`'s `serialize()`, `normalize()`, and `resolve()`, when called with the non-default option `reference: 'suffix'` on a reference that has no authority, emit a relative reference whose first path segment contains a bare colon without escaping it. RFC 3986 section 3.3 requires the first segment of a `path-noscheme` reference not to contain a colon, precisely because a bare colon makes the string reparse as an absolute URI with a scheme. `fast-uri`'s default serialization escapes that colon, but the suffix path does not.\n\nFor example, `normalize('javascript:alert(1)', { reference: 'suffix' })` returns `javascript:alert(1)`, which reparses as a live `javascript:` scheme; `data:` and `vbscript:` behave the same.\n\nApplications that serialize or normalize a relative reference with `reference: 'suffix'` and then treat the result as a URI can turn inert input into a live `javascript:`, `data:`, or `vbscript:` URL (a cross-site scripting vector), and `equal()` can conflate a scheme-bearing reference with a relative one. Exposure is limited to applications that use the non-default `reference: 'suffix'` option.\n\n### Patches\n\nUpgrade to `fast-uri` `2.4.8`, `3.1.9`, or `4.2.3`.\n\n### Workarounds\n\nDo not use the `reference: 'suffix'` option on untrusted input. If suffix output is required, percent-encode a colon in the first path segment of the result before treating it as a URI.\n\n## Affected packages\n\n- `fast-uri < 2.4.8`\n- `fast-uri >= 3.0.0, < 3.1.9`\n- `fast-uri >= 4.0.0, < 4.2.3`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `fast-uri 2.4.8`\n- `fast-uri 3.1.9`\n- `fast-uri 4.2.3`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Low · affected: Cost Management On Premise, Cryostat 4, Migration Toolkit for Applications 8, Multicluster Engine for Kubernetes, Network Observability Operator, OpenShift Lightspeed, … · no fix planned: Red Hat Ansible Automation Platform 2, Red Hat Directory Server 11, Red Hat Directory Server 12, Red Hat Openshift Data Foundation 4, … · updated 2026-10-20 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-110725.json)","depth":"sunlit","depthScore":20,"depthScoreParts":{"impact":20.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}