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💎 RubyGems
Not in CISA KEV
HIGH severity

CVE-2021-4250 — active_attr

HIGHFix: cgriego/active_attr@dab95e5

CVE-2021-4250 is a high-severity (CVSS 7.5) CWE-404 vulnerability in active_attr. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for active_attr — see the affected versions and patch details below.

active_attr Improper Resource Shutdown or Release vulnerability

Also known asGHSA-4whf-rmx5-8frv
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.2%probability of exploitation in next 30 days
Lower Risk+0.04%
Lower risk than most CVEs68th percentile — riskier than 68% of all scored CVEsHighest risk
0.38%0.81%1.25%1.68%0.9%1.2%May 26Aug 26Nov 26

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
💎active_attr

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

A vulnerability classified as problematic has been found in cgriego active_attr up to 0.15.2. This affects the function call of the file lib/active_attr/typecasting/boolean_typecaster.rb of the component Regex Handler. The manipulation of the argument value leads to denial of service. The exploit has been disclosed to the public and may be used. Upgrading to version 0.15.3 is able to address this issue. The name of the patch is dab95e5843b01525444b82bd7b336ef1d79377df. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-216207.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsactive_attrall versions0.15.4bundle update active_attr --conservative

Affected Products

1 product · 1 configurations
Application
active attractive_attr_project
< 0.15.3
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.

A vulnerability classified as problematic has been found in cgriego acti…

github.comNVDJan 2023

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update active_attr to 0.15.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-4250 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

A vulnerability classified as problematic has been found in cgriego active_attr up to 0.15.2. This affects the function call of the file lib/active_attr/typecasting/boolean_typecaster.rb of the component Regex Handler. The manipulation of the argument value leads to denial of service. The exploit has been disclosed to the public and may be used. Upgrading to version 0.15.3 is able to address this issue. The name of the patch is dab95e5843b01525444b82bd7b336ef1d79377df. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-216207.
O3 Security · Impact-Aware SCA

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CVE-2021-4250: active_attr DoS — Fixed in 0.15.4