Use after free in Mozilla Firefox ESR
Priority MEDIUM 43CWE-416Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 16 fixed, 1 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
Summary
When processing callbacks that occurred during window flushing in the parent process, the associated window may die; causing a use-after-free condition. This could have led to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.10, Firefox < 78, and Thunderbird < 68.10.0.
Why it matters now
EPSS 0.02322 83rd percentileScored 2026-11-07
Fix Partial Firefox ESR (Mozilla): 68.10Firefox (Mozilla): 78+1 more productRed Hat: 10 advisoriesRed Hat: 16 fixed, 1 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mozilla | Firefox ESR | before 68.10 | 68.10 | Patch available | CNA |
| Mozilla | Firefox | before 78 | 78 | Patch available | CNA |
| Mozilla | Thunderbird | before 68.10.0 | 68.10.0 | Patch available | CNA |
- Firefox ESR VendorMozilla Affected before 68.10 Fixed in 68.10 Patch available CNA
- Firefox VendorMozilla Affected before 78 Fixed in 78 Patch available CNA
- Thunderbird VendorMozilla Affected before 68.10.0 Fixed in 68.10.0 Patch available CNA
CPE configurations NVD · 9
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | before 78.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* | before 68.10 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | before 68.10.0 | Vulnerable | Mozilla |
| cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:* | 16.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* | 18.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:* | 19.10 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:* | 20.04 | Vulnerable | Canonical |
| cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* | 15.1 | Vulnerable | openSUSE |
| cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:* | 15.2 | Vulnerable | openSUSE |
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 78.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 68.10 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 68.10.0 Vulnerable ·Mozilla
- cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:* Versions 16.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* Versions 18.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:* Versions 19.10 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:* Versions 20.04 Vulnerable ·Canonical
- cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* Versions 15.1 Vulnerable ·openSUSE
- cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:* Versions 15.2 Vulnerable ·openSUSE
Remediation
- Fix · CNA Firefox ESR (Mozilla) Fixed in 68.10
- Fix · CNA Firefox (Mozilla) Fixed in 78
- Fix · CNA Thunderbird (Mozilla) Fixed in 68.10.0
Red Hat 10 advisories
- RHSA-2020:3038 Released 2020-07-21 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-68.10.0-1.el8_2
- RHSA-2020:3046 Released 2020-07-21 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird-68.10.0-1.el8_0
- RHSA-2020:2966 Released 2020-07-16 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Desktop (v. 6) thunderbird-68.10.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) thunderbird-68.10.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) thunderbird-68.10.0-1.el6_10
Show 7 more Red Hat advisories
- RHSA-2020:2906 Released 2020-07-14 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Client (v. 7) thunderbird-68.10.0-1.el7_8
- Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-68.10.0-1.el7_8
- Red Hat Enterprise Linux Workstation (v. 7) thunderbird-68.10.0-1.el7_8
- RHSA-2020:2907 Released 2020-07-14 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-68.10.0-1.el8_1
- RHSA-2020:2827 Released 2020-07-06 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Client (v. 7) firefox-68.10.0-1.el7_8
- Red Hat Enterprise Linux Client Optional (v. 7) firefox-68.10.0-1.el7_8
- Red Hat Enterprise Linux Server (v. 7) firefox-68.10.0-1.el7_8
- Red Hat Enterprise Linux Server Optional (v. 7) firefox-68.10.0-1.el7_8
- Red Hat Enterprise Linux Workstation (v. 7) firefox-68.10.0-1.el7_8
- Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-68.10.0-1.el7_8
- RHSA-2020:2828 Released 2020-07-06 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-68.10.0-1.el8_2
- RHSA-2020:2826 Released 2020-07-06 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-68.10.0-1.el8_1
- RHSA-2020:2824 Released 2020-07-06 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Desktop (v. 6) firefox-68.10.0-1.el6_10
- Red Hat Enterprise Linux Desktop Optional (v. 6) firefox-68.10.0-1.el6_10
- Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox-68.10.0-1.el6_10
- Red Hat Enterprise Linux Server (v. 6) firefox-68.10.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) firefox-68.10.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) firefox-68.10.0-1.el6_10
- Red Hat Enterprise Linux Workstation Optional (v. 6) firefox-68.10.0-1.el6_10
- RHSA-2020:2825 Released 2020-07-06 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-68.10.0-1.el8_0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — openSUSE-SU-2020:0983
13 records Highest priority Priority MEDIUM 6 MEDIUM, 7 LOW
Other records, highest priority first
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
- TI-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — openSUSE-SU-2020:1017
13 records Highest priority Priority MEDIUM 6 MEDIUM, 7 LOW
Other records, highest priority first
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
- TI-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
Show 5 more groups
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — GLSA-202007-10
12 records Highest priority Priority MEDIUM 6 MEDIUM, 6 LOW
Other records, highest priority first
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
- TI-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — USN-4421-1
10 records Highest priority Priority MEDIUM 5 MEDIUM, 5 LOW
Other records, highest priority first
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
- TI-2020-09928 Out-of-bounds write in Mozilla ThunderbirdPriority MEDIUM 42
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — openSUSE-SU-2020:0967
5 records Highest priority Priority MEDIUM 3 MEDIUM, 2 LOW
Other records, highest priority first
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
- TI-2020-09936 Out-of-bounds read in Mozilla Firefox ESRPriority LOW 34
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — openSUSE-SU-2020:0982
5 records Highest priority Priority MEDIUM 3 MEDIUM, 2 LOW
Other records, highest priority first
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
- TI-2020-09936 Out-of-bounds read in Mozilla Firefox ESRPriority LOW 34
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — GLSA-202007-09
5 records Highest priority Priority MEDIUM 3 MEDIUM, 2 LOW
Other records, highest priority first
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
- TI-2020-09936 Out-of-bounds read in Mozilla Firefox ESRPriority LOW 34
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2020:2828, RHSA-2020:3038 |
| Red Hat Enterprise Linux AppStream E4S (v. 8.0) | Fixed | RHSA-2020:2825, RHSA-2020:3046 |
| Red Hat Enterprise Linux AppStream EUS (v. 8.1) | Fixed | RHSA-2020:2826, RHSA-2020:2907 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2020:2827, RHSA-2020:2906 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2020:2827 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2020:2824, RHSA-2020:2966 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2020:2824 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2020:2824 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2020:2824 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2020:2827 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2020:2824, RHSA-2020:2966 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2020:2827, RHSA-2020:2906 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2020:2824, RHSA-2020:2966 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2020:2827, RHSA-2020:2906 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2020:2824 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2020:2827 |
Timeline
- 2026-10-02 Threatist record created from CVE-2020-12419
- 2026-10-03 Alias added: GHSA-qfjv-j5f5-wv79
References
Advisory 11
- https://www.mozilla.org/security/advisories/mfsa2020-24/
- https://www.mozilla.org/security/advisories/mfsa2020-26/
- https://www.mozilla.org/security/advisories/mfsa2020-25/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1643874
- openSUSE-SU-2020:0967
- openSUSE-SU-2020:0982
- openSUSE-SU-2020:0983
- openSUSE-SU-2020:1017
- USN-4421-1
- GLSA-202007-09
- GLSA-202007-10
More Mozilla Firefox vulnerabilities
- TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
- TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
- TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
- TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
- TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
- TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
Sources
- CVE-2020-12419 · CVE Program
- CVE-2020-12419 · NVD
- FIRST EPSS
- GHSA-qfjv-j5f5-wv79 · GitHub Advisory Database · CC BY 4.0
- CVE-2020-12419 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences