# Firefox Esr vulnerabilities > Firefox Esr is made by Mozilla. We track 743 published vulnerabilities in it, across 200 versions. 5 of them are on the list of flaws known to be exploited, the newest added on 23 May 2022. If you run Firefox Esr, check your version against the exploited flaws below and patch those first. Canonical page: https://www.precursorintelligence.com/product/mozilla/firefox_esr ## At a glance - **Made by:** [Mozilla](https://www.precursorintelligence.com/vendors/mozilla) - **Published vulnerabilities:** 743 - **Known to be exploited:** 5 - **Versions tracked:** 200 - **Most recently added to the known-exploited list:** [CVE-2019-11708](https://www.precursorintelligence.com/what-is/cve-2019-11708), 23 May 2022. We keep watching the list. ## Which Firefox Esr vulnerabilities are being exploited? 5 flaws are on the government list of vulnerabilities known to be exploited, newest first: - [CVE-2019-11708](https://www.precursorintelligence.com/what-is/cve-2019-11708): Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability. Critical, CVSS 10.0, chance of use in 30 days 56%, known exploited since 23 May 2022. - [CVE-2022-26485](https://www.precursorintelligence.com/what-is/cve-2022-26485): Mozilla Firefox Use-After-Free Vulnerability. High, CVSS 8.8, chance of use in 30 days 14%, known exploited since 7 March 2022. - [CVE-2022-26486](https://www.precursorintelligence.com/what-is/cve-2022-26486): Mozilla Firefox Use-After-Free Vulnerability. Critical, CVSS 9.6, chance of use in 30 days 2.4%, known exploited since 7 March 2022. - [CVE-2020-6819](https://www.precursorintelligence.com/what-is/cve-2020-6819): Mozilla Firefox And Thunderbird Use-After-Free Vulnerability. High, CVSS 8.1, chance of use in 30 days 3.0%, known exploited since 3 November 2021. - [CVE-2020-6820](https://www.precursorintelligence.com/what-is/cve-2020-6820): Mozilla Firefox And Thunderbird Use-After-Free Vulnerability. High, CVSS 8.1, chance of use in 30 days 7.1%, known exploited since 3 November 2021. ## Which Firefox Esr flaws are most likely to be used? Ranked by the latest exploit-likelihood forecast (the chance each flaw is used in an attack in the next 30 days): - [CVE-2015-4000](https://www.precursorintelligence.com/what-is/cve-2015-4000): >99%, Low (CVSS 3.7) - [CVE-2014-1511](https://www.precursorintelligence.com/what-is/cve-2014-1511): 84%, Critical (CVSS 9.8) - [CVE-2014-1510](https://www.precursorintelligence.com/what-is/cve-2014-1510): 82%, Critical (CVSS 9.8) - [CVE-2015-0816](https://www.precursorintelligence.com/what-is/cve-2015-0816): 67%, Medium (CVSS 5.0) - [CVE-2019-11708](https://www.precursorintelligence.com/what-is/cve-2019-11708): 56%, Critical (CVSS 10.0), known exploited - [CVE-2020-26950](https://www.precursorintelligence.com/what-is/cve-2020-26950): 42%, High (CVSS 8.8) - [CVE-2017-5375](https://www.precursorintelligence.com/what-is/cve-2017-5375): 34%, Critical (CVSS 9.8) - [CVE-2019-9810](https://www.precursorintelligence.com/what-is/cve-2019-9810): 30%, High (CVSS 8.8) - [CVE-2022-1802](https://www.precursorintelligence.com/what-is/cve-2022-1802): 27%, High (CVSS 8.8) ## Questions ### How many vulnerabilities does Firefox Esr have? We track 743 published vulnerabilities listed under the name Firefox Esr, across 200 versions. The most recent Firefox Esr flaw added to the known-exploited list is CVE-2019-11708, on 23 May 2022. ### Which Firefox Esr vulnerabilities are being exploited? 5 are on the list of flaws known to be exploited. The most recently added are CVE-2019-11708, CVE-2022-26485 and CVE-2022-26486. ### How do I get alerts for Firefox Esr? Create a Precursor Intelligence account and track Firefox Esr. We match it against every published flaw, give each one a risk score from 0 to 100 and keep watching, so you hear about new ones as soon as we know, by email, in the app or by webhook. ## Running Firefox Esr? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact