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Fencer Intel
medium 4.3

CVE-2009-5017 json

Mozilla Firefox before 3.6 Beta 3 does not properly handle overlong UTF-8 encoding, which makes it easier for remote attackers to bypass cr…

published 15y ago modified 4mo ago also EUVD-2009-4975

cvss
4.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

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.

Patch / fix

  • firefox RHEL 5 3.6.4-8.el5
  • esc RHEL 5 1.1.0-12.el5
  • yelp RHEL 5 2.16.0-26.el5
  • totem RHEL 5 2.16.7-7.el5
  • devhelp RHEL 5 0.12-21.el5
  • xulrunner RHEL 5 1.9.2.4-10.el5
  • totem-mozplugin RHEL 5 2.16.7-7.el5
  • gnome-python2-extras RHEL 5 2.14.2-7.el5

red hat advisories RHSA-2010:0501RHSA-2010:0500

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-5017 updated cvss 4.3

Firefox: overlong UTF-8 seqence detection problem

  • Red Hat Enterprise Linux (v. 5 server) esc 1.1.0-12.el5, totem 2.16.7-7.el5, yelp 2.16.0-26.el5, devhelp 0.12-21.el5, firefox 3.6.4-8.el5, xulrunner 1.9.2.4-10.el5, +6 more
    fixed: vendor fix RHSA-2010:0501
  • Red Hat Enterprise Linux AS version 4 firefox 3.6.4-8.el4
    fixed: vendor fix RHSA-2010:0500
  • Red Hat Enterprise Linux Desktop (v. 5 client) esc 1.1.0-12.el5, totem 2.16.7-7.el5, yelp 2.16.0-26.el5, devhelp 0.12-21.el5, firefox 3.6.4-8.el5, xulrunner 1.9.2.4-10.el5, +6 more
    fixed: vendor fix RHSA-2010:0501
  • Red Hat Enterprise Linux Desktop version 4 firefox 3.6.4-8.el4
    fixed: vendor fix RHSA-2010:0500
  • Red Hat Enterprise Linux Desktop Workstation (v. 5 client) totem 2.16.7-7.el5, devhelp 0.12-21.el5, xulrunner 1.9.2.4-10.el5, totem-mozplugin 2.16.7-7.el5
    fixed: vendor fix RHSA-2010:0501
  • Red Hat Enterprise Linux ES version 4 firefox 3.6.4-8.el4 Red Hat Enterprise Linux WS version 4 firefox 3.6.4-8.el4
    fixed: vendor fix RHSA-2010:0500

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.83% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • sirdarckcat.blogspot.com http://sirdarckcat.blogspot.com/2009/10/couple-of-unicode-issues-on-php-and.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.