CVE-2020-1913 is a high-severity (CVSS 8.1) CWE-195 vulnerability in hermes-engine. A fix is available for hermes-engine — see the affected versions and patch details below.
Signed to Unsigned Conversion Error in Facebook Hermes
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, a proxy for how much of the ecosystem is exposed.
hermes-enginenpmDescription
An Integer signedness error in the JavaScript Interpreter in Facebook Hermes prior to commit 2c7af7ec481ceffd0d14ce2d7c045e475fd71dc6 allows attackers to cause a denial of service attack or a potential RCE via crafted JavaScript. Note that this is only exploitable if the application using Hermes permits evaluation of untrusted JavaScript. Hence, most React Native applications are not affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | hermes-engine | all versions | 0.5.2npm install hermes-engine@0.5.2 |
Affected Products
hermesfacebookDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hermes-engine, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update hermes-engine to 0.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-1913 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-2020-1913 in your dependencies?
Find it across npm, including transitive dependencies.