Description
A use-after-free vulnerability can occur while parsing an HTML5 stream in concert with custom HTML elements. This results in the stream parser object being freed while still in use, leading to a potentially exploitable crash. This vulnerability affects Thunderbird < 60.5, Firefox ESR < 60.5, and Firefox < 65.
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 | 60.5.0esr-1 | — |
| Debian 14 | thunderbird | 1:60.5.0-1 | — |
| Debian 13 | firefox-esr | 60.5.0esr-1 | — |
| Debian 13 | thunderbird | 1:60.5.0-1 | — |
| Debian 12 | firefox-esr | 60.5.0esr-1 | — |
| Debian 12 | thunderbird | 1:60.5.0-1 | — |
| Debian 9 | firefox-esr | 60.5.0esr-1~deb9u1 | DSA-4376-1 |
| Debian 9 | thunderbird | 1:60.5.1-1~deb9u1 | DSA-4392-1 |
| Debian 8 | firefox-esr | 60.5.0esr-1~deb8u1 | DLA-1648-1 |
| Debian 8 | thunderbird | 1:60.5.1-1~deb8u1 | DLA-1678-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | mozjs52 | No fix yet | — |
| Ubuntu 18.04 LTS | firefox | 65.0+build2-0ubuntu0.18.04.1 | USN-3874-1 |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | thunderbird | 1:60.5.1+build2-0ubuntu0.18.04.1 | USN-3897-1 |
| Ubuntu 16.04 LTS | firefox | 65.0+build2-0ubuntu0.16.04.1 | USN-3874-1 |
| Ubuntu 16.04 LTS | thunderbird | 1:60.5.1+build2-0ubuntu0.16.04.1 | USN-3897-1 |
| Ubuntu 14.04 LTS | firefox | 65.0+build2-0ubuntu0.14.04.1 | USN-3874-1 |
| Ubuntu 14.04 LTS | thunderbird | 1:60.5.1+build2-0ubuntu0.14.04.1 | USN-3897-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | firefox | 60.5.0-2.el7 | RHSA-2019:0219 |
| RHEL 7 | thunderbird | 60.5.0-1.el7_6 | RHSA-2019:0270 |
| RHEL 6 | firefox | 60.5.0-2.el6 | RHSA-2019:0218 |
| RHEL 6 | thunderbird | 60.5.0-1.el6_10 | RHSA-2019:0269 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 | MozillaFirefox | 60.5.0-3.24.2 | SUSE-SU-2019:0273-1 |
| SLES 15 | MozillaThunderbird | 60.5.0-3.20.2 | SUSE-SU-2019:0338-1 |
| SLES 15 | mozilla-nss | 3.41.1-3.13.1 | SUSE-SU-2019:0273-1 |
| SLES 12 SP4 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SLES 12 SP4 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SLES 12 SP4 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
| SLES 12 SP3 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SLES 12 SP3 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SLES 12 SP3 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
| SLES 12 SP2 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SLES 12 SP2 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SLES 12 SP2 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
| SLES 12 SP1 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SLES 12 SP1 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SLES 12 SP1 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SLES 12 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SLES 12 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP4 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP4 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP3 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP3 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP2 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP2 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
| SLES for SAP 12 SP1 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-2 |
| SLES for SAP 12 SP1 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-2 |
| SLES for SAP 12 SP1 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-2 |
| SUSE Package Hub 12 | MozillaThunderbird | 60.5.1-79.1 | openSUSE-SU-2019:0249-1 |
| SUSE OpenStack Cloud 7 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SUSE OpenStack Cloud 7 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SUSE OpenStack Cloud 7 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
| SUSE Enterprise Storage 4 | MozillaFirefox | 60.5.0esr-109.58.3 | SUSE-SU-2019:0336-1 |
| SUSE Enterprise Storage 4 | MozillaFirefox-branding-SLE | 60-32.5.1 | SUSE-SU-2019:0336-1 |
| SUSE Enterprise Storage 4 | mozilla-nss | 3.41.1-58.25.1 | SUSE-SU-2019:0336-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 92.0-1.2 | openSUSE-SU-2024:10600-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 91.1.1-1.1 | openSUSE-SU-2024:10601-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
| openSUSE Leap 15.0 | MozillaFirefox | 60.8.0-lp150.3.62.1 | openSUSE-SU-2019:1758-1 |
| openSUSE Leap 15.0 | mozilla-nss | 3.41.1-lp150.2.20.1 | openSUSE-SU-2019:1758-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.23 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.22 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.21 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.20 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.19 | firefox-esr | 60.5.0-r0 | — |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.18 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.17 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.16 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.15 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.14 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.13 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.12 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.11 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.10 | firefox-esr | 60.5.0-r0 | — |
| Alpine v3.9 | firefox-esr | 60.5.0-r0 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | firefox | 60.5.0-2.0.1.el7 | ELSA-2019-0219 |
| Oracle Linux 7 | thunderbird | 60.5.0-1.0.1.el7_6 | ELSA-2019-0270 |
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.
GitHub 1 repository
-
sophoslabs/CVE-2018-18500 ★ 61 · Apr 18, 2019
PoC for CVE-2018-18500 - Firefox Use-After-Free
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 21
- RHSA-2019:0270 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2019:0269 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2019:0219 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2019:0218 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-3897-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-3874-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4392-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-4376-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1678-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1648-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2019:1758-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:0336-2 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10600-1 MozillaFirefox-92.0-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:0338-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:0336-1 Security update for MozillaFirefox 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
- SUSE-SU-2019:0273-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10601-1 MozillaThunderbird-91.1.1-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- openSUSE-SU-2019:0249-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · May 2, 2025
- ELSA-2019-0270 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 4, 2019
- ELSA-2019-0219 Critical: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 31, 2019
References
- RHSA-2019:0219 vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2019-01/
- USN-3897-1 vendor-advisory
- 106781 vdb-entry
- GLSA-201903-04 vendor-advisory
- USN-3874-1 vendor-advisory
- RHSA-2019:0269 vendor-advisory
- RHSA-2019:0218 vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2019-02/
- DSA-4376 vendor-advisory
- [debian-lts-announce] 20190216 [SECURITY] [DLA 1678-1] thunderbird security update mailing-list
- [debian-lts-announce] 20190130 [SECURITY] [DLA 1648-1] firefox-esr security update mailing-list
- https://www.mozilla.org/security/advisories/mfsa2019-03/
- DSA-4392 vendor-advisory
- RHSA-2019:0270 vendor-advisory
- GLSA-201904-07 vendor-advisory
- openSUSE-SU-2019:1758 vendor-advisory