Description
A use-after-free vulnerability can occur in WebSockets when the object holding the connection is freed before the disconnection operation is finished. This results in an exploitable crash. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | unspecified – < 52.3 | 52.3 |
| Mozilla | Firefox ESR | unspecified – < 52.3 | 52.3 |
| Mozilla | Firefox | unspecified – < 55 | 55 |
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 | 52.3.0esr-1 | — |
| Debian 13 | firefox-esr | 52.3.0esr-1 | — |
| Debian 12 | firefox-esr | 52.3.0esr-1 | — |
| Debian 9 | firefox-esr | 52.3.0esr-1~deb9u1 | DSA-3928-1 |
| Debian 9 | icedove | 1:52.3.0-4~deb9u1 | DSA-3968-1 |
| Debian 8 | firefox-esr | 52.3.0esr-1~deb8u2 | DSA-3928-1 |
| Debian 8 | icedove | 1:52.3.0-4~deb8u2 | DSA-3968-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 7 | firefox-esr | 52.3.0esr-1~deb7u1 | DLA-1053-1 |
| Debian 7 | icedove | 1:52.3.0-4~deb7u1 | DLA-1087-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | thunderbird | 1:52.4.0+build1-0ubuntu2 | — |
| Ubuntu 16.04 LTS | firefox | 55.0.1+build2-0ubuntu0.16.04.2 | USN-3391-1 |
| Ubuntu 16.04 LTS | thunderbird | 1:52.3.0+build1-0ubuntu0.16.04.1 | USN-3416-1 |
| Ubuntu 14.04 LTS | firefox | 55.0.1+build2-0ubuntu0.14.04.2 | USN-3391-1 |
| Ubuntu 14.04 LTS | thunderbird | 1:52.3.0+build1-0ubuntu0.14.04.1 | USN-3416-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | firefox | 52.3.0-2.el7_4 | RHSA-2017:2456 |
| RHEL 7 | thunderbird | 52.3.0-1.el7_4 | RHSA-2017:2534 |
| RHEL 6 | firefox | 52.3.0-3.el6_9 | RHSA-2017:2456 |
| RHEL 6 | thunderbird | 52.3.0-1.el6_9 | RHSA-2017:2534 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | MozillaFirefox | 52.3.0esr-109.3.1 | SUSE-SU-2017:2589-1 |
| SLES 12 SP2 | MozillaFirefox | 52.3.0esr-109.3.1 | SUSE-SU-2017:2589-1 |
| SLES 12 SP1 | MozillaFirefox | 52.3.0esr-109.3.1 | SUSE-SU-2017:2589-1 |
| SLES 12 | MozillaFirefox | 52.3.0esr-109.3.1 | SUSE-SU-2017:2589-1 |
| SLES 11 SP4 | MozillaFirefox | 52.3.0esr-72.9.1 | SUSE-SU-2017:2302-1 |
| SLES 11 SP4 | MozillaFirefox-branding-SLED | 52-24.5.1 | SUSE-SU-2017:2302-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 11 SP3 | MozillaFirefox | 52.3.0esr-72.9.1 | SUSE-SU-2017:2302-1 |
| SLES 11 SP3 | MozillaFirefox-branding-SLED | 52-24.5.1 | SUSE-SU-2017:2302-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 52.3.0esr-109.3.1 | SUSE-SU-2017:2589-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 52.3.0esr-109.3.1 | SUSE-SU-2017:2589-1 |
| SLES for SAP 12 SP1 | MozillaFirefox | 52.3.0esr-109.3.1 | SUSE-SU-2017:2589-1 |
| SLES for SAP 11 SP4 | MozillaFirefox | 52.3.0esr-72.9.1 | SUSE-SU-2017:2302-1 |
| SLES for SAP 11 SP4 | MozillaFirefox-branding-SLED | 52-24.5.1 | SUSE-SU-2017:2302-1 |
| SUSE Package Hub 12 | MozillaThunderbird | 52.3.0-42.1 | openSUSE-SU-2017:2209-1 |
| SUSE OpenStack Cloud 6 | MozillaFirefox | 52.3.0esr-109.3.1 | SUSE-SU-2017:2589-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | MozillaFirefox | 52.3.0esr-72.9.1 | SUSE-SU-2017:2302-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | MozillaFirefox-branding-SLED | 52-24.5.1 | SUSE-SU-2017:2302-1 |
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 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | firefox | 52.3.0-3.0.1.el6_9 | ELSA-2017-2456 |
| Oracle Linux 7 | thunderbird | 52.3.0-1.0.1.el7_4 | ELSA-2017-2534 |
Advisories 17
- RHSA-2017:2534 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Aug 24, 2026
- RHSA-2017:2456 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Aug 24, 2026
- USN-3416-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-3391-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3968-1 icedove - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3928-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1053-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1087-1 icedove - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2017:2302-1 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-2017:2589-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2017:2209-1 Security update for MozillaThunderbird 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
- WID-SEC-2025-1211 Mozilla Firefox: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 2, 2025
- openSUSE-SU-2024:10601-1 MozillaThunderbird-91.1.1-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- ELSA-2017-2534 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Aug 24, 2017
- ELSA-2017-2456 Critical: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Aug 11, 2017
References
- https://www.mozilla.org/security/advisories/mfsa2017-19/
- https://www.mozilla.org/security/advisories/mfsa2017-20/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1374047
- DSA-3968 vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2017-18/
- RHSA-2017:2456 vendor-advisory
- RHSA-2017:2534 vendor-advisory
- 100196 vdb-entry
- 1039124 vdb-entry
- GLSA-201803-14 vendor-advisory
- DSA-3928 vendor-advisory