CVE-2009-5017

Severity: medium (CVSS 4.3 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2010-11-12 · updated 2026-06-16
Weakness: CWE-79

Description

Mozilla Firefox before 3.6 Beta 3 does not properly handle overlong UTF-8 encoding, which makes it easier for remote attackers to bypass cross-site scripting (XSS) protection mechanisms via a crafted string, a different vulnerability than CVE-2010-1210.

Affected products

Mozilla Firefox: through 3.6; 3.6-beta1

References

http://hg.mozilla.org/releases/mozilla-1.9.2/rev/e42c563313a0
http://sirdarckcat.blogspot.com/2009/10/couple-of-unicode-issues-on-php-and.html
https://bugzilla.mozilla.org/show_bug.cgi?id=511859
https://bugzilla.mozilla.org/show_bug.cgi?id=522634
http://hg.mozilla.org/releases/mozilla-1.9.2/rev/e42c563313a0
http://sirdarckcat.blogspot.com/2009/10/couple-of-unicode-issues-on-php-and.html
https://bugzilla.mozilla.org/show_bug.cgi?id=511859
https://bugzilla.mozilla.org/show_bug.cgi?id=522634

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