Use after free in Mozilla Thunderbird
Priority MEDIUM 41CWE-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: 15 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 a device was changed while a stream was about to be destroyed, the <code>stream-reinit</code> task may have been executed after the stream was destroyed, causing a use-after-free and a potentially exploitable crash. This vulnerability affects Thunderbird < 68.6, Firefox < 74, Firefox < ESR68.6, and Firefox ESR < 68.6.
Why it matters now
EPSS 0.01474 73rd 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-2020-05524 Out-of-bounds write in Mozilla ThunderbirdPriority MEDIUM 46
- TI-2020-05521 Command injection in Mozilla ThunderbirdPriority MEDIUM 44
- TI-2020-05516 Out-of-bounds read in Mozilla ThunderbirdPriority MEDIUM 43
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-2020-6807
- 2026-10-03 Alias added: GHSA-v7mh-jh5r-f65h
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-2020-6807 · CVE Program
- CVE-2020-6807 · NVD
- FIRST EPSS
- GHSA-v7mh-jh5r-f65h · GitHub Advisory Database · CC BY 4.0
- CVE-2020-6807 · 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