# CVE-2025-57821: Basecamp's Google Sign-In for Rails allowed redirects to a malformed URL

> CVE-2025-57821: Basecamp's Google Sign-In for Rails allowed redirects to a malformed URL. CVSS 4.2 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2025-57821
Last updated: 2026-06-17T09:43:30Z

- Published: 2025-08-27 16:32 UTC · Updated: 2026-06-17 09:43 UTC · Assigner: GitHub\_M
- CVSS: 4.2 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
- EPSS: 0.24%, 15th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-601

## Description

Basecamp's Google Sign-In adds Google sign-in to Rails applications. Prior to version 1.3.0, it is possible to craft a malformed URL that passes the "same origin" check, resulting in the user being redirected to another origin. Rails applications configured to store the flash information in a session cookie may be vulnerable, if this can be chained with an attack that allows injection of arbitrary data into the session cookie. This issue has been patched in version 1.3.0. If upgrading is not possible at this time, a way to mitigate the chained attack can be done by explicitly setting SameSite=Lax or SameSite=Strict on the application session cookie.

## Affected vendors and products

- basecamp: google\_sign\_in

## Tracked companies

- [Basecamp](https://rewindex.com/company/basecamp.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2025-57821)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2025-57821)
- [https://github.com/basecamp/google\_sign\_in/commit/85903651201257d4f14b97d4582e6d968ac32f15](https://github.com/basecamp/google_sign_in/commit/85903651201257d4f14b97d4582e6d968ac32f15)
- [https://github.com/basecamp/google\_sign\_in/pull/73](https://github.com/basecamp/google_sign_in/pull/73)
- [https://github.com/basecamp/google\_sign\_in/releases/tag/v1.3.0](https://github.com/basecamp/google_sign_in/releases/tag/v1.3.0)
- [https://github.com/basecamp/google\_sign\_in/security/advisories/GHSA-7pwc-wh6m-44q3](https://github.com/basecamp/google_sign_in/security/advisories/GHSA-7pwc-wh6m-44q3)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2025-57821 · Markdown: https://rewindex.com/cve/CVE-2025-57821.md · JSON: https://rewindex.com/api/v1/cves/CVE-2025-57821 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T04:06:17.688Z