# CVE-2019-11756: Firefox ESR: Improper refcounting of soft token session objects could cause a use-after-free and crash (likely limited… CVE-2019-11756 is fixed in 16 products on 2 platforms, first by firefox 71.0+build5-0ubuntu0.18.04.1, released December 3, 2019. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2019-11756 - Priority: High - CVSS: 8.8 (Moderate) - EPSS: 0.0149 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Dec 3, 2019 - Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2019-11756 ## Description Improper refcounting of soft token session objects could cause a use-after-free and crash (likely limited to a denial of service). This vulnerability affects Firefox < 71. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Windows apps | Mozilla Firefox ESR (en-US) | 78.0esr | [Mozilla Firefox ESR (en-US) 78.0esr](https://patchblox.com/security/data/fix/windows-app/mozilla.firefox.esr-78.0esr.md) | Jun 25, 2020 | | Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 71.0+build5-0ubuntu0.18.04.1 | [firefox 71.0+build5-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-71.0-build5-0ubuntu0.18.04.1.md) | Dec 3, 2019 | | Linux | firefox Ubuntu 20.04 LTS (focal) | 71.0+build5-0ubuntu1 | [firefox 71.0+build5-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-71.0-build5-0ubuntu1.md) | Dec 3, 2019 | | Linux | firefox-geckodriver Ubuntu 18.04.6 LTS (bionic) | 71.0+build5-0ubuntu0.18.04.1 | [firefox-geckodriver 71.0+build5-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-geckodriver-71.0-build5-0ubuntu0.18.04.1.md) | Dec 3, 2019 | | Linux | firefox-geckodriver Ubuntu 20.04 LTS (focal) | 71.0+build5-0ubuntu1 | [firefox-geckodriver 71.0+build5-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-geckodriver-71.0-build5-0ubuntu1.md) | Dec 3, 2019 | | Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 71.0+build5-0ubuntu0.18.04.1 | [firefox-mozsymbols 71.0+build5-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-71.0-build5-0ubuntu0.18.04.1.md) | Dec 3, 2019 | | Linux | firefox-mozsymbols Ubuntu 20.04 LTS (focal) | 71.0+build5-0ubuntu1 | [firefox-mozsymbols 71.0+build5-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-mozsymbols-71.0-build5-0ubuntu1.md) | Dec 3, 2019 | | Linux | nspr RHEL 8 | 0:4.25.0-2.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nspr ol 8 | 0:4.25.0-2.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nspr-devel RHEL 8 | 0:4.25.0-2.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nspr-devel ol 8 | 0:4.25.0-2.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-devel RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-devel ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-softokn RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-softokn ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-softokn-devel RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-softokn-devel ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-softokn-freebl RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-softokn-freebl ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-softokn-freebl-devel RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-softokn-freebl-devel ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-sysinit RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-sysinit ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-tools RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-tools ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-util RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-util ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | | Linux | nss-util-devel RHEL 8 | 0:3.53.1-11.el8_2 | [RHSA-2020:3280](https://patchblox.com/security/data/fix/linux/rhsa-2020-3280.md) | Aug 3, 2020 | | Linux | nss-util-devel ol 8 | 0:3.53.1-11.el8_2 | [ELSA-2020-3280](https://patchblox.com/security/data/fix/linux/elsa-2020-3280.md) | Aug 4, 2020 | --- Data as of 2026-11-08T00:53:09Z UTC. 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