How severe is CVE-2010-1987?

CVE-2010-1987 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2010-1987 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2010-1987?

CVE-2010-1987 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2010-1987?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2010-1987 published?

CVE-2010-1987 was published on 2010-05-20 and last updated on 2026-06-16.

CVE-2010-1987

CVE-2010-1987 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 5.0. 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-399.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 2% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-399
Affected product: Mozilla Firefox
Published: 2010-05-20
Last modified: 2026-06-16

Description

Mozilla Firefox 3.6.3 on Windows XP SP3 allows remote attackers to cause a denial of service (memory consumption, out-of-bounds read, and application crash) via JavaScript code that appends long strings to the content of a P element, and performs certain other string concatenation and substring operations, related to the DoubleWideCharMappedString class in USP10.dll and the gfxWindowsFontGroup::GetUnderlineOffset function in xul.dll, a different vulnerability than CVE-2009-1571.

Frequently asked questions

What is CVE-2010-1987?: Mozilla Firefox 3.6.3 on Windows XP SP3 allows remote attackers to cause a denial of service (memory consumption, out-of-bounds read, and application crash) via JavaScript code that appends long strings to the content of a P element, and performs certain other string concatenation and substring operations, related to the DoubleWideCharMappedString class in USP10.dll and the gfxWindowsFontGroup::GetUnderlineOffset function in xul.dll, a different vulnerability than CVE-2009-1571.
How severe is CVE-2010-1987?: CVE-2010-1987 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2010-1987 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2010-1987?: CVE-2010-1987 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2010-1987?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2010-1987 published?: CVE-2010-1987 was published on 2010-05-20 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:3.6.3:*:*:*:*:*:*:*

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