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.NET
.NET NuGet
Not in CISA KEV
HIGH severity

CVE-2018-0856 — Microsoft.ChakraCore

HIGHFix: chakra-core/ChakraCore@385af84

CVE-2018-0856 is a high-severity (CVSS 7.5) Out-of-bounds Write vulnerability in Microsoft.ChakraCore. EPSS puts its 30-day exploitation probability at 15.4% (97th percentile). A fix is available for Microsoft.ChakraCore — see the affected versions and patch details below.

ChakraCore RCE Vulnerability

Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
15.4%probability of exploitation in next 30 days
Moderate Risk0.00%
Lower risk than most CVEs97th percentile — riskier than 97% of all scored CVEsHighest risk
11.5%18.5%25.4%32.3%28.4%15.4%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
.NETMicrosoft.ChakraCore

Real-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

Microsoft Edge and ChakraCore in Microsoft Windows 10 1703 and 1709 allows remote code execution, due to how the scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2018-0834, CVE-2018-0835, CVE-2018-0836, CVE-2018-0837, CVE-2018-0838, CVE-2018-0840, CVE-2018-0857, CVE-2018-0858, CVE-2018-0859, CVE-2018-0860, CVE-2018-0861, and CVE-2018-0866.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetMicrosoft.ChakraCoreall versions1.8.1dotnet add package Microsoft.ChakraCore --version 1.8.1

Affected Products

2 products · 2 configurations
Application
chakracoremicrosoft
all
Application
edgemicrosoft
all

Detection & mitigation playbook

Open-source dependency

  1. Detect

    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.

  2. Fix

    Update Microsoft.ChakraCore to 1.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-0856 is resolved across your whole dependency graph.

  3. 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

Microsoft Edge and ChakraCore in Microsoft Windows 10 1703 and 1709 allows remote code execution, due to how the scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2018-0834, CVE-2018-0835, CVE-2018-0836, CVE-2018-0837, CVE-2018-0838, CVE-2018-0840, CVE-2018-0857, CVE-2018-0858, CVE-2018-0859, CVE-2018-0860, CVE-2018-0861, and CVE-2018-0866.
O3 Security · Impact-Aware SCA

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CVE-2018-0856: Microsoft.ChakraCore RCE — Fixed in 1.8.1