How severe is CVE-2018-8403?

CVE-2018-8403 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-2018-8403 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-8403?

CVE-2018-8403 primarily affects Microsoft Internet Explorer. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-8403?

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-2018-8403 published?

CVE-2018-8403 was published on 2018-08-15 and last updated on 2026-06-17.

CVE-2018-8403

CVE-2018-8403 is a high-severity vulnerability in Microsoft Internet Explorer with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 13% places it in the 96th 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: 13% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Microsoft Internet Explorer
Published: 2018-08-15
Last modified: 2026-06-17

Description

A remote code execution vulnerability exists in the way that Microsoft browsers access objects in memory, aka "Microsoft Browser Memory Corruption Vulnerability." This affects Internet Explorer 11, Microsoft Edge, Internet Explorer 10.

Frequently asked questions

What is CVE-2018-8403?: A remote code execution vulnerability exists in the way that Microsoft browsers access objects in memory, aka "Microsoft Browser Memory Corruption Vulnerability." This affects Internet Explorer 11, Microsoft Edge, Internet Explorer 10.
How severe is CVE-2018-8403?: CVE-2018-8403 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-2018-8403 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-8403?: CVE-2018-8403 primarily affects Microsoft Internet Explorer. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-8403?: 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-2018-8403 published?: CVE-2018-8403 was published on 2018-08-15 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:microsoft:internet_explorer:11:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:edge:-:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:internet_explorer:10:*:*:*:*:*:*:*

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