CVE-2009-2463

CVE-2009-2463 is a critical-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 10.0. 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-189.

Key facts

• Severity: Critical (CVSS 2.0 base score 10.0)
• EPSS exploit prediction: 6% (93rd percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-189
• Affected product: Mozilla Firefox
• Published: 2009-07-22
• Last modified: 2026-06-16

Description

Multiple integer overflows in the (1) PL_Base64Decode and (2) PL_Base64Encode functions in nsprpub/lib/libc/src/base64.c in Mozilla Firefox before 3.0.12, Thunderbird before 2.0.0.24, and SeaMonkey before 1.1.19 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors that trigger buffer overflows.

Frequently asked questions

What is CVE-2009-2463?

Multiple integer overflows in the (1) PL_Base64Decode and (2) PL_Base64Encode functions in nsprpub/lib/libc/src/base64.c in Mozilla Firefox before 3.0.12, Thunderbird before 2.0.0.24, and SeaMonkey before 1.1.19 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors that trigger buffer overflows.

How severe is CVE-2009-2463?

CVE-2009-2463 has a CVSS 2.0 base score of 10.0, rated critical severity.

Is CVE-2009-2463 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-2463?

CVE-2009-2463 primarily affects Mozilla Firefox. In total, 123 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-2463?

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-2009-2463 published?

CVE-2009-2463 was published on 2009-07-22 and last updated on 2026-06-16.

References

• http://lists.opensuse.org/opensuse-security-announce/2009-07/msg00005.html
• http://lists.opensuse.org/opensuse-security-announce/2009-08/msg00002.html
• http://lists.opensuse.org/opensuse-security-announce/2010-06/msg00001.html
• http://rhn.redhat.com/errata/RHSA-2009-1162.html
• http://rhn.redhat.com/errata/RHSA-2009-1163.html
• http://secunia.com/advisories/35914
• http://secunia.com/advisories/35943
• http://secunia.com/advisories/35944
• http://secunia.com/advisories/35947
• http://secunia.com/advisories/36005
• http://secunia.com/advisories/36145
• http://secunia.com/advisories/38977
• http://secunia.com/advisories/39001
• http://sunsolve.sun.com/search/document.do?assetkey=1-26-265068-1
• http://sunsolve.sun.com/search/document.do?assetkey=1-77-1020800.1-1
• http://www.mozilla.org/security/announce/2009/mfsa2009-34.html
• http://www.mozilla.org/security/announce/2010/mfsa2010-07.html
• http://www.redhat.com/support/errata/RHSA-2010-0153.html
• http://www.redhat.com/support/errata/RHSA-2010-0154.html
• http://www.securityfocus.com/bid/35758
• http://www.ubuntu.com/usn/USN-915-1
• http://www.vupen.com/english/advisories/2009/1972
• http://www.vupen.com/english/advisories/2009/2152
• http://www.vupen.com/english/advisories/2010/0648
• http://www.vupen.com/english/advisories/2010/0650
• https://bugzilla.mozilla.org/show_bug.cgi?id=492779
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10369
• https://www.redhat.com/archives/fedora-package-announce/2009-July/msg01032.html

Affected products (123)

• cpe:2.3:a:mozilla:firefox:0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.6:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.6.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.7:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.7.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.8:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9:rc:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.9_rc:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.10:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:0.10.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0:preview_release:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.6:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.6:*:linux:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.7:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.0.8:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.4.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5:beta1:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5:beta2:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.6:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:1.5.0.7:*:*:*:*:*:*:*

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