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Fencer Vulns
critical 9.3

CVE-2009-1840 json

Mozilla Firefox before 3.0.11, Thunderbird, and SeaMonkey do not check content policy before loading a script file into a XUL document, whi…

published 2009-06-12 17 y ago modified 2026-06-16 4 mo ago also EUVD-2009-1835

cvss
9.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

Mozilla Firefox before 3.0.11, Thunderbird, and SeaMonkey do not check content policy before loading a script file into a XUL document, which allows remote attackers to bypass intended access restrictions via a crafted HTML document, as demonstrated by a "web bug" in an e-mail message, or web script or an advertisement in a web page.

Patch / fix

  • firefox RHEL 4 3.0.11-4.el4
  • firefox RHEL 5 3.0.11-2.el5_3
  • xulrunner RHEL 5 1.9.0.11-3.el5_3
  • xulrunner-devel-unstable RHEL 5 1.9.0.11-3.el5_3

red hat advisories RHSA-2009:1095

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-2009-1840 updated cvss 1.8

Firefox XUL scripts skip some security checks

  • Red Hat Enterprise Linux (v. 5 server) firefox 3.0.11-2.el5_3, xulrunner 1.9.0.11-3.el5_3, xulrunner-devel-unstable 1.9.0.11-3.el5_3 Red Hat Enterprise Linux AS version 4 firefox 3.0.11-4.el4 Red Hat Enterprise Linux Desktop (v. 5 client) firefox 3.0.11-2.el5_3, xulrunner 1.9.0.11-3.el5_3, xulrunner-devel-unstable 1.9.0.11-3.el5_3 Red Hat Enterprise Linux Desktop version 4 firefox 3.0.11-4.el4 Red Hat Enterprise Linux Desktop Workstation (v. 5 client) xulrunner 1.9.0.11-3.el5_3, xulrunner-devel-unstable 1.9.0.11-3.el5_3 Red Hat Enterprise Linux ES version 4 firefox 3.0.11-4.el4
    +1 more products
    Red Hat Enterprise Linux WS version 4 firefox 3.0.11-4.el4
    fixed: vendor fix RHSA-2009:1095

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

2.22% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

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-264 Permissions, Privileges, and Access Controls

References

Sources

Fencer Vulns 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.