Out-of-bounds write in Mozilla Firefox ESR
Priority MEDIUM 47CWE-787Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- 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-787 and the CVSS impact.
Summary
Mozilla developers and community members reported memory safety bugs present in Firefox 75 and Firefox ESR 68.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 68.8, Firefox < 76, and Thunderbird < 68.8.0.
Why it matters now
EPSS 0.02597 85th percentileScored 2026-11-07
Fix Partial Firefox ESR (Mozilla): 68.8Firefox (Mozilla): 76+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 68.8 | 68.8 | Patch available | CNA |
| Mozilla | Firefox | before 76 | 76 | Patch available | CNA |
| Mozilla | Thunderbird | before 68.8.0 | 68.8.0 | Patch available | CNA |
- Firefox ESR VendorMozilla Affected before 68.8 Fixed in 68.8 Patch available CNA
- Firefox VendorMozilla Affected before 76 Fixed in 76 Patch available CNA
- Thunderbird VendorMozilla Affected before 68.8.0 Fixed in 68.8.0 Patch available CNA
CPE configurations NVD · 7
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | before 76.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* | before 68.8.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | before 68.8.0 | 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:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 76.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 68.8.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 68.8.0 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
Remediation
- Fix · CNA Firefox ESR (Mozilla) Fixed in 68.8
- Fix · CNA Firefox (Mozilla) Fixed in 76
- Fix · CNA Thunderbird (Mozilla) Fixed in 68.8.0
Red Hat 10 advisories
- RHSA-2020:2050 Released 2020-05-11 · Red Hat rating Criticalthunderbird security update
- Red Hat Enterprise Linux Client (v. 7) thunderbird-68.8.0-1.el7_8
- Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-68.8.0-1.el7_8
- Red Hat Enterprise Linux Workstation (v. 7) thunderbird-68.8.0-1.el7_8
- RHSA-2020:2049 Released 2020-05-11 · Red Hat rating Criticalthunderbird security update
- Red Hat Enterprise Linux Desktop (v. 6) thunderbird-68.8.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) thunderbird-68.8.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) thunderbird-68.8.0-1.el6_10
- RHSA-2020:2046 Released 2020-05-11 · Red Hat rating Criticalthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-68.8.0-1.el8_2
Show 7 more Red Hat advisories
- RHSA-2020:2047 Released 2020-05-11 · Red Hat rating Criticalthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-68.8.0-1.el8_1
- RHSA-2020:2048 Released 2020-05-11 · Red Hat rating Criticalthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird-68.8.0-1.el8_0
- RHSA-2020:2036 Released 2020-05-06 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux Desktop (v. 6) firefox-68.8.0-1.el6_10
- Red Hat Enterprise Linux Desktop Optional (v. 6) firefox-68.8.0-1.el6_10
- Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox-68.8.0-1.el6_10
- Red Hat Enterprise Linux Server (v. 6) firefox-68.8.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) firefox-68.8.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) firefox-68.8.0-1.el6_10
- Red Hat Enterprise Linux Workstation Optional (v. 6) firefox-68.8.0-1.el6_10
- RHSA-2020:2037 Released 2020-05-06 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux Client (v. 7) firefox-68.8.0-1.el7_8
- Red Hat Enterprise Linux Client Optional (v. 7) firefox-68.8.0-1.el7_8
- Red Hat Enterprise Linux Server (v. 7) firefox-68.8.0-1.el7_8
- Red Hat Enterprise Linux Server Optional (v. 7) firefox-68.8.0-1.el7_8
- Red Hat Enterprise Linux Workstation (v. 7) firefox-68.8.0-1.el7_8
- Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-68.8.0-1.el7_8
- RHSA-2020:2031 Released 2020-05-06 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-68.8.0-1.el8_2
- RHSA-2020:2032 Released 2020-05-06 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-68.8.0-1.el8_1
- RHSA-2020:2033 Released 2020-05-06 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-68.8.0-1.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 — USN-4373-1
5 records Highest priority Priority MEDIUM 2 MEDIUM, 3 LOW
Other records, highest priority first
- TI-2020-05540 Out-of-bounds write in Mozilla Firefox ESRPriority MEDIUM 51
- TI-2020-09905 Race condition in Mozilla Firefox ESRPriority LOW 38
- TI-2020-09910 Path traversal in Mozilla Firefox ESRPriority LOW 25
Vendor assessments
Red Hat
Red Hat rating: Critical. 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-2020:2031, RHSA-2020:2046 |
| Red Hat Enterprise Linux AppStream E4S (v. 8.0) | Fixed | RHSA-2020:2033, RHSA-2020:2048 |
| Red Hat Enterprise Linux AppStream EUS (v. 8.1) | Fixed | RHSA-2020:2032, RHSA-2020:2047 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2020:2037, RHSA-2020:2050 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2020:2037 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2020:2036, RHSA-2020:2049 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2020:2036 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2020:2036 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2020:2036 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2020:2037 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2020:2036, RHSA-2020:2049 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2020:2037, RHSA-2020:2050 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2020:2036, RHSA-2020:2049 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2020:2037, RHSA-2020:2050 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2020:2036 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2020:2037 |
Timeline
- 2026-10-02 Threatist record created from CVE-2020-12395
- 2026-10-03 Alias added: GHSA-v3wf-5473-qgjv
References
Advisory 6
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-2020-12395 · CVE Program
- CVE-2020-12395 · NVD
- FIRST EPSS
- GHSA-v3wf-5473-qgjv · GitHub Advisory Database · CC BY 4.0
- CVE-2020-12395 · Red Hat security data · CC BY 4.0
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