CVE-2017-11870 is a high-severity (CVSS 7.5) Buffer Overflow vulnerability in Microsoft.ChakraCore. 3 public exploit references exist, so weaponization risk is real. A fix is available for Microsoft.ChakraCore — see the affected versions and patch details below.
Chakra Core vulnerable to privilege escalation when writing to JavaScript null scope objects
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2017-11870 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
ChakraCore and Microsoft Edge in Windows 10 1703, 1709, and Windows Server, version 1709 allows an attacker to gain the same user rights as the current user, due to how the scripting engine handles objects in memory. This could be exploited using write-AV when writing to a slot of a JavaScript null scope object.
This CVE ID is unique from CVE-2017-11836, CVE-2017-11837, CVE-2017-11838, CVE-2017-11839, CVE-2017-11840, CVE-2017-11841, CVE-2017-11843, CVE-2017-11846, CVE-2017-11858, CVE-2017-11859, CVE-2017-11861, CVE-2017-11862, CVE-2017-11866, CVE-2017-11869, CVE-2017-11871, and CVE-2017-11873.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.ChakraCore | all versions | 1.7.4dotnet add package Microsoft.ChakraCore --version 1.7.4 |
Research 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 JIT - Incorrect Function Declaration Scope
by Google Security Research · Nov 27, 2017
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 1.7.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-11870 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2017-11870 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2017-11870. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2017-11870 in your dependencies?
O3 Security finds CVE-2017-11870 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.