Description
Mozilla Firefox before 3.0.15 and 3.5.x before 3.5.4, and SeaMonkey before 2.0, does not properly handle a right-to-left override (aka RLO or U+202E) Unicode character in a download filename, which allows remote attackers to spoof file extensions via a crafted filename, as demonstrated by displaying a non-executable extension for an executable file.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 5.0 | xulrunner | 1.9.0.15-0lenny1 | DSA-1922-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | firefox | 3.0.15-3.el5_4 | RHSA-2009:1530 |
| RHEL 5 | nspr +1 | 4.7.6-1.el5_4 | RHSA-2009:1530 |
| RHEL 5 | thunderbird | 2.0.0.24-2.el5_4 | RHSA-2010:0153 |
| RHEL 5 | xulrunner +2 | 1.9.0.15-3.el5_4 | RHSA-2009:1530 |
| RHEL 4 | firefox | 3.0.15-3.el4 | RHSA-2009:1530 |
| RHEL 4 | nspr +1 | 4.7.6-1.el4_8 | RHSA-2009:1530 |
| RHEL 4 | seamonkey +5 | 1.0.9-50.el4_8 | RHSA-2009:1531 |
| RHEL 4 | thunderbird | 1.5.0.12-25.el4 | RHSA-2010:0154 |
| RHEL 3 | seamonkey +9 | 1.0.9-0.47.el3 | RHSA-2009:1531 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Rhel Productivity 5 | thunderbird | 2.0.0.24-2.el5_4 | RHSA-2010:0153 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 50.1.0-1.1 | openSUSE-SU-2024:10071-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
Advisories 7
- RHSA-2009:1530 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2010:0154 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2009:1531 Red Hat Security Advisory: seamonkey security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-1922-1 xulrunner - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:14572-1 firefox-esr-128.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2010:0153 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jan 14, 2026
- openSUSE-SU-2024:10071-1 MozillaFirefox-50.1.0-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
References
- RHSA-2010:0153 vendor-advisory
- ADV-2010-0648 vdb-entry
- ADV-2010-0650 vdb-entry
- 272909 vendor-advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=511521
- SUSE-SR:2010:013 vendor-advisory
- 38977 third-party-advisory
- RHSA-2010:0154 vendor-advisory
- http://www.mozilla.org/security/announce/2009/mfsa2009-62.html
- oval:org.mitre.oval:def:11218 vdb-entry signature
- USN-915-1 vendor-advisory
- oval:org.mitre.oval:def:6541 vdb-entry signature
- ADV-2009-3334 vdb-entry
- MDVSA-2009:294 vendor-advisory