How severe is CVE-2018-8391?

CVE-2018-8391 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-8391 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-8391?

CVE-2018-8391 affects Microsoft Chakracore. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-8391?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-8391 published?

CVE-2018-8391 was published on 2018-09-13 and last updated on 2026-06-17.

CVE-2018-8391

CVE-2018-8391 is a high-severity vulnerability in Microsoft Chakracore with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 11% places it in the 95th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.6
EPSS exploit prediction: 11% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Microsoft Chakracore
Published: 2018-09-13
Last modified: 2026-06-17

Description

A remote code execution vulnerability exists in the way that the ChakraCore scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability." This affects ChakraCore. This CVE ID is unique from CVE-2018-8354, CVE-2018-8456, CVE-2018-8457, CVE-2018-8459.

Frequently asked questions

What is CVE-2018-8391?: A remote code execution vulnerability exists in the way that the ChakraCore scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability." This affects ChakraCore. This CVE ID is unique from CVE-2018-8354, CVE-2018-8456, CVE-2018-8457, CVE-2018-8459.
How severe is CVE-2018-8391?: CVE-2018-8391 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-8391 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-8391?: CVE-2018-8391 affects Microsoft Chakracore. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-8391?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-8391 published?: CVE-2018-8391 was published on 2018-09-13 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:microsoft:chakracore:-:*:*:*:*:*:*:*

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