Out-of-bounds write in Mozilla Thunderbird
Priority MEDIUM 46CWE-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: 15 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 reported memory safety bugs present in Firefox and Thunderbird 68.5. 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 Thunderbird < 68.6, Firefox < 74, Firefox < ESR68.6, and Firefox ESR < 68.6.
Why it matters now
EPSS 0.01869 79th percentileScored 2026-11-07
Fix Partial Thunderbird (Mozilla): 68.6Firefox (Mozilla): 74, ESR68.6+1 more productRed Hat: 8 advisoriesRed Hat: 15 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 | Thunderbird | before 68.6 | 68.6 | Patch available | CNA |
| Mozilla | Firefox | before 74; before ESR68.6 | 74, ESR68.6 | Patch available | CNA |
| Mozilla | Firefox ESR | before 68.6 | 68.6 | Patch available | CNA |
- Thunderbird VendorMozilla Affected before 68.6 Fixed in 68.6 Patch available CNA
- Firefox VendorMozilla Affected before 74; before ESR68.6 Fixed in 74, ESR68.6 Patch available CNA
- Firefox ESR VendorMozilla Affected before 68.6 Fixed in 68.6 Patch available CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | before 74.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* | before 68.6.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | before 68.6.0 | 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:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 74.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 68.6.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 68.6.0 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
Remediation
- Fix · CNA Thunderbird (Mozilla) Fixed in 68.6
- Fix · CNA Firefox (Mozilla) Fixed in 74, ESR68.6
- Fix · CNA Firefox ESR (Mozilla) Fixed in 68.6
Red Hat 8 advisories
- RHSA-2020:0914 Released 2020-03-23 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Desktop (v. 6) thunderbird-68.6.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) thunderbird-68.6.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) thunderbird-68.6.0-1.el6_10
- RHSA-2020:0919 Released 2020-03-23 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-68.6.0-1.el8_1
- RHSA-2020:0918 Released 2020-03-23 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird-68.6.0-1.el8_0
Show 5 more Red Hat advisories
- RHSA-2020:0905 Released 2020-03-19 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Client (v. 7) thunderbird-68.6.0-1.el7_7
- Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-68.6.0-1.el7_7
- Red Hat Enterprise Linux Workstation (v. 7) thunderbird-68.6.0-1.el7_7
- RHSA-2020:0820 Released 2020-03-16 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-68.6.0-1.el8_1
- RHSA-2020:0819 Released 2020-03-16 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-68.6.0-1.el8_0
- RHSA-2020:0816 Released 2020-03-16 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Desktop (v. 6) firefox-68.6.0-1.el6_10
- Red Hat Enterprise Linux Desktop Optional (v. 6) firefox-68.6.0-1.el6_10
- Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox-68.6.0-1.el6_10
- Red Hat Enterprise Linux Server (v. 6) firefox-68.6.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) firefox-68.6.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) firefox-68.6.0-1.el6_10
- Red Hat Enterprise Linux Workstation Optional (v. 6) firefox-68.6.0-1.el6_10
- RHSA-2020:0815 Released 2020-03-16 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Client (v. 7) firefox-68.6.0-1.el7_7
- Red Hat Enterprise Linux Client Optional (v. 7) firefox-68.6.0-1.el7_7
- Red Hat Enterprise Linux Server (v. 7) firefox-68.6.0-1.el7_7
- Red Hat Enterprise Linux Server Optional (v. 7) firefox-68.6.0-1.el7_7
- Red Hat Enterprise Linux Workstation (v. 7) firefox-68.6.0-1.el7_7
- Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-68.6.0-1.el7_7
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Mozilla Firefox, Firefox ESR, Thunderbird 68.6, 74, ESR68.6
6 records Highest priority Priority MEDIUM 5 MEDIUM, 1 LOW
Other records, highest priority first
- TI-2020-05521 Command injection in Mozilla ThunderbirdPriority MEDIUM 44
- TI-2020-05516 Out-of-bounds read in Mozilla ThunderbirdPriority MEDIUM 43
- TI-2020-05517 Use after free in Mozilla ThunderbirdPriority MEDIUM 41
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-2020:0820, RHSA-2020:0919 |
| Red Hat Enterprise Linux AppStream E4S (v. 8.0) | Fixed | RHSA-2020:0819, RHSA-2020:0918 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2020:0815, RHSA-2020:0905 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2020:0815 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2020:0816, RHSA-2020:0914 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2020:0816 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2020:0816 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2020:0816 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2020:0815 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2020:0816, RHSA-2020:0914 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2020:0815, RHSA-2020:0905 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2020:0816, RHSA-2020:0914 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2020:0815, RHSA-2020:0905 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2020:0816 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2020:0815 |
Timeline
- 2026-10-02 Threatist record created from CVE-2020-6814
- 2026-10-03 Alias added: GHSA-36f2-2h7g-5h9g
References
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-2020-6814 · CVE Program
- CVE-2020-6814 · NVD
- FIRST EPSS
- GHSA-36f2-2h7g-5h9g · GitHub Advisory Database · CC BY 4.0
- CVE-2020-6814 · Red Hat security data · CC BY 4.0
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