How severe is CVE-2008-5021?

CVE-2008-5021 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2008-5021 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2008-5021?

CVE-2008-5021 primarily affects Mozilla Firefox. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2008-5021?

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-2008-5021 published?

CVE-2008-5021 was published on 2008-11-13 and last updated on 2026-06-16.

CVE-2008-5021

CVE-2008-5021 is a critical-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 9.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-362.

Key facts

Severity: Critical (CVSS 2.0 base score 9.3)
EPSS exploit prediction: 4% (88th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-362
Affected product: Mozilla Firefox
Published: 2008-11-13
Last modified: 2026-06-16

Description

nsFrameManager in Firefox 3.x before 3.0.4, Firefox 2.x before 2.0.0.18, Thunderbird 2.x before 2.0.0.18, and SeaMonkey 1.x before 1.1.13 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code by modifying properties of a file input element while it is still being initialized, then using the blur method to access uninitialized memory.

Frequently asked questions

What is CVE-2008-5021?: nsFrameManager in Firefox 3.x before 3.0.4, Firefox 2.x before 2.0.0.18, Thunderbird 2.x before 2.0.0.18, and SeaMonkey 1.x before 1.1.13 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code by modifying properties of a file input element while it is still being initialized, then using the blur method to access uninitialized memory.
How severe is CVE-2008-5021?: CVE-2008-5021 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2008-5021 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2008-5021?: CVE-2008-5021 primarily affects Mozilla Firefox. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2008-5021?: 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-2008-5021 published?: CVE-2008-5021 was published on 2008-11-13 and last updated on 2026-06-16.

References

Affected products (21)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:4.0:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:6.06:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:7.10:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:8.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:8.10:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:8:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:9:*:*:*:*:*:*:*
cpe:2.3:a:suse:linux_enterprise_debuginfo:10:sp2:*:*:*:*:*:*
cpe:2.3:o:novell:linux_desktop:9:*:*:*:*:*:*:*
cpe:2.3:o:novell:open_enterprise_server:-:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:opensuse:10.2:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:opensuse:10.3:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:opensuse:11.0:*:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_desktop:10:-:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_server:9:*:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_server:10:sp1:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_software_development_kit:10:sp1:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_software_development_kit:10:sp2:*:*:*:*:*:*

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