{"id":"CVE-2026-42259","aliases":["GHSA-f3g8-9xv5-77gv"],"url":"https://o3.security/vulnerability/CVE-2026-42259","summary":"Saltcorn: Open Redirect in `POST /auth/login` due to incomplete `is_relative_url` validation (backslash bypass)","details":"Saltcorn is an extensible, open source, no-code database application builder. Prior to versions 1.4.6, 1.5.6, and 1.6.0-beta.5, Saltcorn validates the post-login dest parameter with a string check that only blocks :/ and //. Because all WHATWG-compliant browsers normalise backslashes (\\) to forward slashes (/) for special schemes, a payload such as /\\evil.com/path slips through is_relative_url(), is emitted unchanged in the HTTP Location header, and causes the browser to navigate cross-origin to an attacker-controlled domain. The bug is reachable on a default install and only requires a victim who can be tricked into logging in via a crafted Saltcorn URL. This issue has been patched in versions 1.4.6, 1.5.6, and 1.6.0-beta.5.","published":"2026-05-07T18:54:57.234Z","modified":"2026-08-07T11:31:34.871721335Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"@saltcorn/server","fixedVersion":"1.4.6"},{"ecosystem":"npm","name":"@saltcorn/server","fixedVersion":"1.5.6"},{"ecosystem":"npm","name":"@saltcorn/server","fixedVersion":"1.6.0-beta.5"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42259.json"},{"type":"ADVISORY","url":"https://github.com/saltcorn/saltcorn/security/advisories/GHSA-f3g8-9xv5-77gv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42259"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:31:34.871721335Z"}}