CVE-2009-5017
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.
Does this matter?
Lower severity and a low EPSS score (1.83%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 2.0
- 4.3 MEDIUMAV:N/AC:M/Au:N/C:N/I:P/A:N
- EPSS
- 1.83% probability · 79th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Affected
- mozilla/firefox
- Source
- cve@mitre.org
EPSS 1.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
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.htmlExploit
- https://bugzilla.mozilla.org/show_bug.cgi?id=511859Patch
- 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.htmlExploit
- https://bugzilla.mozilla.org/show_bug.cgi?id=511859Patch
- https://bugzilla.mozilla.org/show_bug.cgi?id=522634
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.