Skip to content
Fencer Intel
critical 9.3

CVE-2012-4204 json

The str_unescape function in the JavaScript engine in Mozilla Firefox before 17.0, Thunderbird before 17.0, and SeaMonkey before 2.14 allow…

published 2012-11-21 13 y ago modified 2026-06-16 4 mo ago also EUVD-2012-4148

cvss
9.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
5.8%
EPSS 5.8% chance of exploitation in 30 days, percentile 93%
public exploits
0
none known

Summary

The str_unescape function in the JavaScript engine in Mozilla Firefox before 17.0, Thunderbird before 17.0, and SeaMonkey before 2.14 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via unspecified vectors.

Patch / fix

  • mozilla firefox 17.0
  • mozilla seamonkey 2.14
  • mozilla thunderbird 17.0
  • 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-2012-4204 updated cvss 6.8

Mozilla: Memory corruption in str_unescape (MFSA 2012-96)

  • Red Hat Enterprise Linux 5 firefox, thunderbird Red Hat Enterprise Linux 6 firefox, thunderbird
    not affected: vulnerable code not present

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

5.78% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=778603 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 9.3 AV:N/AC:M/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

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.