Google Sign-In for Rails allowed redirects to malformed URLs

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

4.2 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

EPSS

• CVE-2025-57821: 0.25% estimated exploitation activity in the next 30 days; percentile 16.42 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary It is possible to craft a malformed URL that passes the "same origin" check, resulting in the user being redirected to another origin. Details The googlesignin gem persists an optional URL for redirection after authentication. If this URL is malformed, it's possible for the user to be redirected to another origin after authentication, possibly resulting in exposure of authentication information such as the token. Normally the value of this URL is only written and read by the library. If applications are configured to store session information in a database, there is no known vector to exploit this vulnerability. However, applications may be configured to store this information in a session cookie, in which case it may be chained with a session cookie attack to inject a crafted URL. Impact 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…

Published by the source

27 Aug 2025, 16:46 UTC

Last modified by the source

29 Aug 2025, 15:22 UTC

Source last checked

26 Oct 2026, 15:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7pwc-wh6m-44q3

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2025-57821

Advisory: Google Sign-In for Rails allowed redirects to malformed URLs
IDs: CVE-2025-57821, GHSA-7pwc-wh6m-44q3
Record: https://patchnext.com/advisories/cve-2025-57821 (revision 1, source checked 26 Oct 2026, 15:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: google_sign_in 1.3.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems google_sign_in: affected < 1.3.0; fixed in 1.3.0

## Suggested inspection (read-only)
- RubyGems google_sign_in: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on google_sign_in.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7pwc-wh6m-44q3 (GitHub-reviewed advisory GHSA-7pwc-wh6m-44q3 lists affected ranges: RubyGems google_sign_in >=0 <1.3.0)

Commands are suggestions: review each one before running it.