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Fencer Intel
medium 4.3

CVE-2012-4207 json

The HZ-GB-2312 character-set implementation in Mozilla Firefox before 17.0, Firefox ESR 10.x before 10.0.11, Thunderbird before 17.0, Thund…

published 2012-11-21 13 y ago modified 2026-06-16 4 mo ago also EUVD-2012-4151

cvss
4.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.8%
EPSS 2.8% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

The HZ-GB-2312 character-set implementation in Mozilla Firefox before 17.0, Firefox ESR 10.x before 10.0.11, Thunderbird before 17.0, Thunderbird ESR 10.x before 10.0.11, and SeaMonkey before 2.14 does not properly handle a ~ (tilde) character in proximity to a chunk delimiter, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a crafted document.

Patch / fix

  • mozilla firefox 10.0.11, 17.0
  • mozilla seamonkey 2.14
  • mozilla thunderbird 17.0
  • mozilla thunderbird_esr 10.0.11
  • thunderbird RHEL 5 PRODUCTIVITY, RHEL 5 10.0.11-1.el5_8
  • thunderbird RHEL 6 10.0.11-1.el6_3
  • firefox RHEL 5 10.0.11-1.el5_8
  • firefox RHEL 6 10.0.11-1.el6_3
  • xulrunner RHEL 5 10.0.11-1.el5_8
  • xulrunner RHEL 6 10.0.11-1.el6_3

red hat advisories RHSA-2012:1483RHSA-2012:1482

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 50.1.0-1.1
  • MozillaThunderbird openSUSE Tumbleweed 45.5.1-1.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10071-1openSUSE-SU-2024:10230-1

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-2012-4207 updated cvss 4.3

Mozilla: Improper character decoding in HZ-GB-2312 charset (MFSA 2012-101)

  • Red Hat Enterprise Linux (v. 5 server) firefox 10.0.11-1.el5_8, xulrunner 10.0.11-1.el5_8 Red Hat Enterprise Linux Desktop (v. 5 client) firefox 10.0.11-1.el5_8, xulrunner 10.0.11-1.el5_8, thunderbird 10.0.11-1.el5_8 Red Hat Enterprise Linux Desktop (v. 6) firefox 10.0.11-1.el6_3, xulrunner 10.0.11-1.el6_3, thunderbird 10.0.11-1.el6_3 Red Hat Enterprise Linux Desktop Optional (v. 6) xulrunner 10.0.11-1.el6_3 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 10.0.11-1.el6_3, xulrunner 10.0.11-1.el6_3 Red Hat Enterprise Linux Server (v. 6) firefox 10.0.11-1.el6_3, xulrunner 10.0.11-1.el6_3
    +4 more products
    Red Hat Enterprise Linux Server Optional (v. 6) xulrunner 10.0.11-1.el6_3, thunderbird 10.0.11-1.el6_3 Red Hat Enterprise Linux Workstation (v. 6) firefox 10.0.11-1.el6_3, xulrunner 10.0.11-1.el6_3, thunderbird 10.0.11-1.el6_3 Red Hat Enterprise Linux Workstation Optional (v. 6) xulrunner 10.0.11-1.el6_3 Red Hat RHEL Desktop Workstation (v. 5 client) xulrunner 10.0.11-1.el5_8
    fixed: vendor fix RHSA-2012:1482
  • Red Hat RHEL Optional Productivity Applications (v. 5 server) thunderbird 10.0.11-1.el5_8
    fixed: vendor fix RHSA-2012:1483

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

2.78% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=801681 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.