{"id":"CVE-2026-49820","aliases":["GO-2026-5861"],"url":"https://o3.security/vulnerability/CVE-2026-49820","summary":"Probo has an open redirect bypass via path normalization","details":"### Impact\nProbo's `saferedirect` package validates redirect URLs used across authentication flows (OIDC, SAML, session transfer, OAuth connectors, and trust-center magic links). The validator only inspected the second character of relative paths, so a URL like `/../\\evil.com` passed validation because the second character is `.`. Go's `http.Redirect` normalizes this path to `/\\evil.com` before setting the `Location` header. Browsers can interpret the backslash as a host separator and redirect the user to an external domain (`https://evil.com`), bypassing the intended same-origin restriction. This enables open-redirect phishing: an attacker can craft a `continue` parameter (or embed a malicious URL in a session-transfer token) that appears to originate from a trusted Probo domain but redirects victims elsewhere.\n\n### Patches\nFixed in `go.probo.inc/probo` by normalizing relative paths with `path.Clean` before validation, rejecting backslashes (including\npercent-encoded `%5c`) anywhere in the path, and re-checking the normalized result for protocol-relative and backslash prefixes.\n\nSelf-hosted deployments should upgrade to **probod v0.194.1** or later.\n\nSaaS deployments on getprobo.com are patched.\n\n### Workarounds\nNo practical workaround for self-hosted installations. Upgrade to the patched release.","published":"2026-06-30T18:31:50Z","modified":"2026-07-07T16:11:26.296909694Z","cvss":{"score":4.7,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Go","name":"go.probo.inc/probo","fixedVersion":"0.204.0"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/getprobo/probo/security/advisories/GHSA-x7qq-m748-8p2c"},{"type":"PACKAGE","url":"https://github.com/getprobo/probo"},{"type":"WEB","url":"https://github.com/getprobo/probo/blob/main/SECURITY_NOTES.md"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-07T16:11:26.296909694Z"}}