What is CVE-2017-8658?

CVE-2017-8658 is a critical-severity vulnerability in Microsoft Chakracore, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2017-08-11.

How severe is CVE-2017-8658?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Microsoft Chakracore

CVE-2017-8658

A remote code execution vulnerability exists in the way that the Chakra JavaScript engine renders when handling objects in memory, aka "Scripting Engine Memory Corruption Vulnerability".

Vulnerability class: Buffer Overflow

Published 2017-08-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.201 (97.4th percentile), scored 2026-09-30.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 97.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.201 · newest: 0.201 · change: 0.000

Affected products

Microsoft Chakracore
Microsoft Corporation Chakracore — versions ChakraCore V1.7.1

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

www.securityfocus.com/bid/100036 (VDB Entry, Third Party Advisory, vdb-entry)
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-8658 (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2017-8658?: CVE-2017-8658 is a critical-severity vulnerability in Microsoft Chakracore, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2017-08-11.
How severe is CVE-2017-8658?: Critical severity. CVSS v3 base score is 9.8 out of 10.