CVE-2006-4340

CVE-2006-4340 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 4.0. 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-20.

Key facts

Description

Mozilla Network Security Service (NSS) library before 3.11.3, as used in Mozilla Firefox before 1.5.0.7, Thunderbird before 1.5.0.7, and SeaMonkey before 1.0.5, when using an RSA key with exponent 3, does not properly handle extra data in a signature, which allows remote attackers to forge signatures for SSL/TLS and email certificates, a similar vulnerability to CVE-2006-4339. NOTE: on 20061107, Mozilla released an advisory stating that these versions were not completely patched by MFSA2006-60. The newer fixes for 1.5.0.7 are covered by CVE-2006-5462.

Frequently asked questions

What is CVE-2006-4340?
Mozilla Network Security Service (NSS) library before 3.11.3, as used in Mozilla Firefox before 1.5.0.7, Thunderbird before 1.5.0.7, and SeaMonkey before 1.0.5, when using an RSA key with exponent 3, does not properly handle extra data in a signature, which allows remote attackers to forge signatures for SSL/TLS and email certificates, a similar vulnerability to CVE-2006-4339. NOTE: on 20061107, Mozilla released an advisory stating that these versions were not completely patched by MFSA2006-60. The newer fixes for 1.5.0.7 are covered by CVE-2006-5462.
How severe is CVE-2006-4340?
CVE-2006-4340 has a CVSS 2.0 base score of 4.0, rated medium severity.
Is CVE-2006-4340 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2006-4340?
CVE-2006-4340 primarily affects Mozilla Firefox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2006-4340?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2006-4340 published?
CVE-2006-4340 was published on 2006-09-15 and last updated on 2026-06-16.

References

Affected products (4)

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