Improper Privilege Management in devise_masquerade

Exploitation

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

CVSS

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

EPSS

• CVE-2021-28680: 1.25% estimated exploitation activity in the next 30 days; percentile 69.42 (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.

The devisemasquerade gem before 1.3 allows certain attacks when a password's salt is unknown. An application that uses this gem to let administrators masquerade/impersonate users loses one layer of security protection compared to a situation where Devise (without this extension) is used. If the server-side secretkeybase value became publicly known (for instance if it is committed to a public repository by mistake), there are still other protections in place that prevent an attacker from impersonating any user on the site. When masquerading is not used in a plain Devise application, one must know the password salt of the target user if one wants to encrypt and sign a valid session cookie. When devisemasquerade is used, however, an attacker can decide which user the "back" action will go back to without knowing that user's password salt and simply knowing the user ID, by manipulating the session cookie and pretending that a user is already masqueraded by an administrator.

Published by the source

8 Dec 2021, 19:55 UTC

Last modified by the source

5 Sep 2023, 21:51 UTC

Source last checked

26 Oct 2026, 15:47 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-25f5-gc4h-hc22

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# Patch Next advisory brief: CVE-2021-28680

Advisory: Improper Privilege Management in devise_masquerade
IDs: CVE-2021-28680, GHSA-25f5-gc4h-hc22
Record: https://patchnext.com/advisories/cve-2021-28680 (revision 1, source checked 26 Oct 2026, 15:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: devise_masquerade 1.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems devise_masquerade: affected < 1.3.1; fixed in 1.3.1

## Suggested inspection (read-only)
- RubyGems devise_masquerade: 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 devise_masquerade.
- 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-25f5-gc4h-hc22 (GitHub-reviewed advisory GHSA-25f5-gc4h-hc22 lists affected ranges: RubyGems devise_masquerade >=0 <1.3.1)

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