Description
The URL parsing implementation in Mozilla Firefox before 42.0 improperly recognizes escaped characters in hostnames within Location headers, which allows remote attackers to obtain sensitive information via vectors involving a redirect.
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.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | firefox | 42.0+build2-0ubuntu0.14.04.1 | USN-2785-1 |
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 3
- USN-2785-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- openSUSE-SU-2024:14572-1 firefox-esr-128.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10071-1 MozillaFirefox-50.1.0-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
References
- 1034069 vdb-entry
- GLSA-201512-10 vendor-advisory
- USN-2785-1 vendor-advisory
- http://www.mozilla.org/security/announce/2015/mfsa2015-129.html
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- openSUSE-SU-2015:1942 vendor-advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1211871