CVE-2019-0539 is a high-severity (CVSS 7.5) Out-of-bounds Write vulnerability in Microsoft.ChakraCore. 10 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for Microsoft.ChakraCore — see the affected versions and patch details below.
ChakraCore RCE Vulnerability
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
Microsoft.ChakraCoreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
A remote code execution vulnerability exists in the way that the Chakra scripting engine handles objects in memory in Microsoft Edge, aka "Chakra Scripting Engine Memory Corruption Vulnerability." This affects Microsoft Edge, ChakraCore. This CVE ID is unique from CVE-2019-0567, CVE-2019-0568.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.ChakraCore | all versions | 1.11.5dotnet add package Microsoft.ChakraCore --version 1.11.5 |
Affected Products
chakracoremicrosoftedgemicrosoftResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Microsoft Edge Chakra - 'NewScObjectNoCtor' or 'InitProto' Type Confusion
by Google Security Research · Jan 18, 2019
Microsoft Edge Chakra - 'InitClass' Type Confusion
by Google Security Research · Jan 18, 2019
Microsoft Edge Chakra 1.11.4 - Read Permission via Type Confusion
by Fahad Aid Alharbi · Mar 4, 2019
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.ChakraCore, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Microsoft.ChakraCore to 1.11.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-0539 is resolved across your whole dependency graph.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Frequently Asked Questions
Is CVE-2019-0539 in your dependencies?
Find it across NuGet, including transitive dependencies.