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Fencer Vulns
medium 4.3

CVE-2009-1834 json

Visual truncation vulnerability in netwerk/dns/src/nsIDNService.cpp in Mozilla Firefox before 3.0.11 and SeaMonkey before 1.1.17 allows rem…

published 2009-06-12 17 y ago modified 2026-06-16 4 mo ago also EUVD-2009-1829

cvss
4.3
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.2%
EPSS 3.2% chance of exploitation in 30 days, percentile 88%
public exploits
1
Exploit-DB

Summary

Visual truncation vulnerability in netwerk/dns/src/nsIDNService.cpp in Mozilla Firefox before 3.0.11 and SeaMonkey before 1.1.17 allows remote attackers to spoof the location bar via an IDN with invalid Unicode characters that are displayed as whitespace, as demonstrated by the \u115A through \u115E characters.

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-2009-1834 updated cvss 2.6

Firefox URL spoofing with invalid unicode characters

  • 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

Timeline

  1. First public exploit (EDB-33039)
  2. Published

Exploit prediction

3.23% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-33039 Mozilla Firefox 3.0.10 / SeaMonkey 1.1.16 - Address Bar URI Spoofing remote, 2009-05-11
  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=479413 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-20 Improper Input Validation

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.