Description
Buffer overflow in the International Domain Name (IDN) support in Mozilla Firefox 1.0.6 and earlier, and Netscape 8.0.3.3 and 7.2, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a hostname with all "soft" hyphens (character 0xAD), which is not properly handled by the NormalizeIDN call in nsStandardURL::BuildNormalizedSpec.
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 ↗Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 4 | firefox | 1.0.6-1.4.2 | RHSA-2005:768 |
| RHEL 4 | thunderbird | 1.0.7-1.4.1 | RHSA-2005:791 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Exploit-DB 1
- Mozilla Browsers - 0xAD (HOST:) Remote Heap Buffer Overrun (2) EDB-1224 · remote · Sep 22, 2005 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 5
- RHSA-2005:791 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2005:768 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-868-1 mozilla-thunderbird - several Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-837-1 mozilla-firefox - buffer overflow Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-866-1 mozilla - several Debian Security (DSA / DLA) · Mar 9, 2026
References
- VU#573857 third-party-advisory
- DSA-868 vendor-advisory
- ADV-2005-1824 vdb-entry
- FLSA-2006:168375 vendor-advisory
- ADV-2005-1690 vdb-entry
- 83 third-party-advisory
- 16767 third-party-advisory
- oval:org.mitre.oval:def:1287 vdb-entry signature
- ADV-2005-1691 vdb-entry
- 16764 third-party-advisory
- DSA-837 vendor-advisory
- oval:org.mitre.oval:def:584 vdb-entry signature
- USN-181-1 vendor-advisory
- RHSA-2005:791 vendor-advisory
- 17042 third-party-advisory
- 14784 vdb-entry
- oval:org.mitre.oval:def:9608 vdb-entry signature
- 16766 third-party-advisory
- DSA-866 vendor-advisory
- http://www.security-protocols.com/advisory/sp-x17-advisory.txt
- 20050911 FireFox "Host:" Buffer Overflow is not just exploitable on FireFox mailing-list
- RHSA-2005:769 vendor-advisory
- 1014877 vdb-entry
- http://www.mozilla.org/security/announce/mfsa2005-57.html
- http://www.securiteam.com/securitynews/5RP0B0UGVW.html
- 17284 third-party-advisory
- 19255 vdb-entry
- 17263 third-party-advisory
- RHSA-2005:768 vendor-advisory
- P-303 third-party-advisory government-resource
- GLSA-200509-11 vendor-advisory
- http://www.security-protocols.com/firefox-death.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=307259
- MDKSA-2005:174 vendor-advisory
- 17090 third-party-advisory
- 20050909 Mozilla Firefox "Host:" Buffer Overflow mailing-list
- mozilla-url-bo(22207) vdb-entry