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💎
💎 RubyGems
Not in CISA KEV
HIGH severity

CVE-2023-31606 — RedCloth

HIGHFix: jgarber/redcloth@8b13276

CVE-2023-31606 is a high-severity (CVSS 7.5) CWE-1333 vulnerability in RedCloth. 2 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for RedCloth — see the affected versions and patch details below.

RedCloth Regular Expression Denial of Service issue

Also known asGHSA-qcm3-vfq5-wfr2
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
2 known
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs75th percentile — riskier than 75% of all scored CVEsHighest risk
0.41%0.95%1.48%2.01%0.9%1.5%May 26Sep 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
💎RedCloth

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 Regular Expression Denial of Service (ReDoS) issue was discovered in the sanitize_html function of redcloth gem v4.0.0. This vulnerability allows attackers to cause a Denial of Service (DoS) via supplying a crafted payload.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsRedClothall versions4.3.3bundle update RedCloth --conservative

Affected Products

1 product · 1 configurations
Application
redclothpromptworks
≥ 4.0.0 && ≤ 4.3.2
range
Exploits & PoCs
2

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

A Regular Expression Denial of Service (ReDoS) issue was discovered in t…

github.comNVDJun 2023

Report on github.com

github.comNVDJun 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 RedCloth, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update RedCloth to 4.3.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-31606 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 Regular Expression Denial of Service (ReDoS) issue was discovered in the sanitize_html function of redcloth gem v4.0.0. This vulnerability allows attackers to cause a Denial of Service (DoS) via supplying a crafted payload.
O3 Security · Impact-Aware SCA

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CVE-2023-31606: RedCloth DoS — Fixed in 4.3.3