What’s Vulnerable › Vulnerabilities

CVE-2013-0776

• Severity: medium (CVSS 4.0 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2013-02-19 · updated 2026-06-16
• Weakness: CWE-295

Description

Mozilla Firefox before 19.0, Firefox ESR 17.x before 17.0.3, Thunderbird before 17.0.3, Thunderbird ESR 17.x before 17.0.3, and SeaMonkey before 2.16 allow man-in-the-middle attackers to spoof the address bar by operating a proxy server that provides a 407 HTTP status code accompanied by web script, as demonstrated by a phishing attack on an HTTPS site.

Affected products

• Canonical Ubuntu Linux: 10.04, 11.10, 12.04, 12.10
• Debian Linux: 7.0
• Mozilla Firefox: before 17.0.3; before 19.0 — fixed in 17.0.3, 19.0
• Mozilla Seamonkey: before 2.16 — fixed in 2.16
• Mozilla Thunderbird: before 17.0.3 — fixed in 17.0.3
• Mozilla Thunderbird ESR: before 17.0.3 — fixed in 17.0.3
• Opensuse: 11.4, 12.1, 12.2
• RedHat Enterprise Linux Aus: 5.9
• RedHat Enterprise Linux Desktop: 5.0, 6.0
• RedHat Enterprise Linux Eus: 5.9, 6.3
• RedHat Enterprise Linux Server: 5.0, 6.0
• RedHat Enterprise Linux Workstation: 5.0, 6.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 17.0.3, 19.0; Mozilla Seamonkey 2.16; Mozilla Thunderbird 17.0.3; Mozilla Thunderbird ESR 17.0.3. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2013-02/msg00017.html
• http://lists.opensuse.org/opensuse-updates/2013-02/msg00062.html
• http://rhn.redhat.com/errata/RHSA-2013-0271.html
• http://rhn.redhat.com/errata/RHSA-2013-0272.html
• http://www.debian.org/security/2013/dsa-2699
• http://www.mozilla.org/security/announce/2013/mfsa2013-27.html
• http://www.ubuntu.com/usn/USN-1729-1
• http://www.ubuntu.com/usn/USN-1729-2
• http://www.ubuntu.com/usn/USN-1748-1
• https://bugzilla.mozilla.org/show_bug.cgi?id=796475
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16666
• http://lists.opensuse.org/opensuse-security-announce/2013-02/msg00017.html

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