Description
Integer underflow in the nsHtml5TreeBuilder class in the HTML5 string parser in Mozilla Firefox before 45.0 and Firefox ESR 38.x before 38.7 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) by leveraging mishandling of end tags, as demonstrated by incorrect SVG processing, aka ZDI-CAN-3545.
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 14 | firefox-esr | 45.0esr-1 | — |
| Debian 13 | firefox-esr | 45.0esr-1 | — |
| Debian 12 | firefox-esr | 45.0esr-1 | — |
| Debian 8 | icedove | 38.7.0-1~deb8u1 | DSA-3520-1 |
| Debian 8 | iceweasel | 38.7.0esr-1~deb8u1 | DSA-3510-1 |
| Debian 7 | icedove | 38.7.0-1~deb7u1 | DSA-3520-1 |
| Debian 7 | iceweasel | 38.7.0esr-1~deb7u1 | DSA-3510-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | thunderbird | 1:38.7.2+build1-0ubuntu0.16.04.1 | USN-2934-1 |
| Ubuntu 14.04 LTS | firefox | 45.0+build2-0ubuntu0.14.04.1 | USN-2917-1 |
| Ubuntu 14.04 LTS | thunderbird | 1:38.7.2+build1-0ubuntu0.14.04.1 | USN-2934-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | firefox +1 | 38.7.0-1.el7_2 | RHSA-2016:0460, RHSA-2016:0373 |
| RHEL 6 | firefox +1 | 38.7.0-1.el6_7 | RHSA-2016:0460, RHSA-2016:0373 |
| RHEL 5 | firefox +1 | 38.7.0-1.el5_11 | RHSA-2016:0460, RHSA-2016:0373 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Rhel Productivity 5 | thunderbird | 38.7.0-1.el5_11 | RHSA-2016:0460 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | MozillaFirefox | 38.7.0esr-63.3 | SUSE-SU-2016:0727-1 |
| SLES 12 SP1 | mozilla-nspr | 4.12-12.1 | SUSE-SU-2016:0727-1 |
| SLES 12 SP1 | mozilla-nss | 3.20.2-40.1 | SUSE-SU-2016:0727-1 |
| SLES 12 | MozillaFirefox | 38.7.0esr-63.3 | SUSE-SU-2016:0727-1 |
| SLES 12 | mozilla-nspr | 4.12-12.1 | SUSE-SU-2016:0727-1 |
| SLES 12 | mozilla-nss | 3.20.2-40.1 | SUSE-SU-2016:0727-1 |
| SLES 11 SP4 | MozillaFirefox | 38.7.0esr-37.3 | SUSE-SU-2016:0777-1 |
| SLES 11 SP4 | mozilla-nspr | 4.12-24.1 | SUSE-SU-2016:0777-1 |
| SLES 11 SP4 | mozilla-nss | 3.20.2-28.1 | SUSE-SU-2016:0777-1 |
| SLES 11 SP3 | MozillaFirefox | 38.7.0esr-37.3 | SUSE-SU-2016:0777-1 |
| SLES 11 SP3 | mozilla-nspr | 4.12-24.1 | SUSE-SU-2016:0777-1 |
| SLES 11 SP3 | mozilla-nss | 3.20.2-28.1 | SUSE-SU-2016:0777-1 |
| SLES 11 SP2 | MozillaFirefox | 38.7.0esr-36.3 | SUSE-SU-2016:0909-1 |
| SLES 11 SP2 | mozilla-nspr | 4.12-19.1 | SUSE-SU-2016:0909-1 |
| SLES 11 SP2 | mozilla-nss | 3.20.2-20.1 | SUSE-SU-2016:0909-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | MozillaFirefox | 38.7.0esr-63.3 | SUSE-SU-2016:0727-1 |
| SLES for SAP 12 SP1 | mozilla-nspr | 4.12-12.1 | SUSE-SU-2016:0727-1 |
| SLES for SAP 12 SP1 | mozilla-nss | 3.20.2-40.1 | SUSE-SU-2016:0727-1 |
| SLES for SAP 12 | MozillaFirefox | 38.7.0esr-63.3 | SUSE-SU-2016:0727-1 |
| SLES for SAP 12 | mozilla-nspr | 4.12-12.1 | SUSE-SU-2016:0727-1 |
| SLES for SAP 12 | mozilla-nss | 3.20.2-40.1 | SUSE-SU-2016:0727-1 |
| SLES for SAP 11 SP4 | MozillaFirefox | 38.7.0esr-37.3 | SUSE-SU-2016:0777-1 |
| SLES for SAP 11 SP4 | mozilla-nspr | 4.12-24.1 | SUSE-SU-2016:0777-1 |
| SLES for SAP 11 SP4 | mozilla-nss | 3.20.2-28.1 | SUSE-SU-2016:0777-1 |
| SUSE Package Hub 12 | MozillaThunderbird | 45.2-6.1 | openSUSE-SU-2016:1778-1, openSUSE-SU-2016:1769-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 50.1.0-1.1 | openSUSE-SU-2024:10071-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 45.5.1-1.1 | openSUSE-SU-2024:10230-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | firefox +1 | 38.7.0-1.0.1.el7_2 | ELSA-2016-0460, ELSA-2016-0373 |
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.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 2
- Firefox 44.0.2 - ASM.JS JIT-Spray Remote Code Execution EDB-44294 · remote · Mar 16, 2018 · verified
- Mozilla Firefox < 45.0 - 'nsHtml5TreeBuilder' Use-After-Free (EMET 5.52 Bypass) EDB-42484 · remote · Aug 18, 2017
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 16
- RHSA-2016:0460 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2016:0373 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-2934-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-2917-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3520-1 icedove - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3510-1 iceweasel - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:0727-1 Security update for MozillaFirefox, mozilla-nspr, mozilla-nss SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10230-1 MozillaThunderbird-45.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2016:1778-1 Security update for Mozilla Thunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:0909-1 Security update for MozillaFirefox, mozilla-nspr, mozilla-nss SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2016:1769-1 Security update for Mozilla Thunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:0777-1 Security update for MozillaFirefox, mozilla-nspr, mozilla-nss SUSE / openSUSE Security Updates · Feb 4, 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
- ELSA-2016-0460 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Mar 16, 2016
- ELSA-2016-0373 Critical: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Mar 9, 2016
References
- openSUSE-SU-2016:0894 vendor-advisory
- http://www.mozilla.org/security/announce/2016/mfsa2016-23.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=1246014
- SUSE-SU-2016:0820 vendor-advisory
- openSUSE-SU-2016:1767 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
- openSUSE-SU-2016:0731 vendor-advisory
- SUSE-SU-2016:0727 vendor-advisory
- openSUSE-SU-2016:1778 vendor-advisory
- openSUSE-SU-2016:0876 vendor-advisory
- USN-2917-1 vendor-advisory
- DSA-3520 vendor-advisory
- openSUSE-SU-2016:1769 vendor-advisory
- 44294 exploit
- http://zerodayinitiative.com/advisories/ZDI-16-198/
- SUSE-SU-2016:0909 vendor-advisory
- DSA-3510 vendor-advisory
- openSUSE-SU-2016:0733 vendor-advisory
- 1035215 vdb-entry
- SUSE-SU-2016:0777 vendor-advisory
- GLSA-201605-06 vendor-advisory
- USN-2934-1 vendor-advisory
- 42484 exploit
- USN-2917-2 vendor-advisory
- USN-2917-3 vendor-advisory