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Not in CISA KEV
HIGH severity

Improper Privilege Management in devise_masqueradeGHSA-25f5-gc4h-hc22

HIGHFix: oivoodoo/devise_masquerade#76

GHSA-25f5-gc4h-hc22 is a high-severity (CVSS 8.1) vulnerability in devise_masquerade. 1 public exploit reference exists, so weaponization risk is real. A fix is available for devise_masquerade — see the affected versions and patch details below.

Also known asCVE-2021-28680
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs69th percentile — riskier than 69% of all scored CVEsHighest risk
0.00%0.58%1.17%1.75%0.3%1.3%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

GHSA-25f5-gc4h-hc22 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
💎devise_masquerade

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

The devise_masquerade 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 secret_key_base 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 devise_masquerade 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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsdevise_masqueradeall versions1.3.1bundle update devise_masquerade --conservative

Affected Products

1 product · 1 configurations
Application
devise masqueradedevise_masquerade_project
< 1.3.0
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for devise_masquerade, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update devise_masquerade to 1.3.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-25f5-gc4h-hc22 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

The devise_masquerade 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 `secret_key_base` 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 mu
O3 Security · Impact-Aware SCA

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Improper Privilege Management in devise_masquerade