How severe is CVE-2011-1998?

CVE-2011-1998 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2011-1998 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 21% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-1998?

CVE-2011-1998 affects Microsoft Internet Explorer. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2011-1998?

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

When was CVE-2011-1998 published?

CVE-2011-1998 was published on 2011-10-12 and last updated on 2026-06-16.

CVE-2011-1998

CVE-2011-1998 is a critical-severity vulnerability in Microsoft Internet Explorer with a CVSS 2.0 base score of 9.3. Its EPSS exploit-prediction score of 21% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-908.

Key facts

Severity: Critical (CVSS 2.0 base score 9.3)
EPSS exploit prediction: 21% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-908
Affected product: Microsoft Internet Explorer
Published: 2011-10-12
Last modified: 2026-06-16

Description

Microsoft Internet Explorer 9 does not properly handle objects in memory, which allows remote attackers to execute arbitrary code by accessing an object that was not properly initialized, aka "Jscript9.dll Remote Code Execution Vulnerability."

Frequently asked questions

What is CVE-2011-1998?: Microsoft Internet Explorer 9 does not properly handle objects in memory, which allows remote attackers to execute arbitrary code by accessing an object that was not properly initialized, aka "Jscript9.dll Remote Code Execution Vulnerability."
How severe is CVE-2011-1998?: CVE-2011-1998 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2011-1998 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 21% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-1998?: CVE-2011-1998 affects Microsoft Internet Explorer. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2011-1998?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2011-1998 published?: CVE-2011-1998 was published on 2011-10-12 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:microsoft:internet_explorer:9:*:*:*:*:*:*:*

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