CVE-2021-23341 is a high-severity (CVSS 7.5) vulnerability in prismjs. 4 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for prismjs — see the affected versions and patch details below.
Denial of service in prismjs
EPSS Exploitation Probability
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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
prismjsnpmDescription
The package prismjs before 1.23.0 are vulnerable to Regular Expression Denial of Service (ReDoS) via the prism-asciidoc, prism-rest, prism-tap and prism-eiffel components.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | prismjs | all versions | 1.23.0npm install prismjs@1.23.0 |
Affected Products
prismprismjsResearch 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 dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for prismjs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update prismjs to 1.23.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23341 is resolved across your whole dependency graph.
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
Is CVE-2021-23341 in your dependencies?
Find it across npm, including transitive dependencies.