Race condition in Mozilla Thunderbird
Priority LOW 27CWE-362Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- High
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · 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 browsing a malicious page, a race condition in our SharedWorkerService could occur and lead to a potentially exploitable crash. This vulnerability affects Thunderbird < 68.9.0, Firefox < 77, and Firefox ESR < 68.9.
Why it matters now
EPSS 0.01352 71st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Thunderbird (Mozilla): 68.9.0Firefox (Mozilla): 77+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 | Thunderbird | before 68.9.0 | 68.9.0 | Patch available | CNA |
| Mozilla | Firefox | before 77 | 77 | Patch available | CNA |
| Mozilla | Firefox ESR | before 68.9 | 68.9 | Patch available | CNA |
- Thunderbird VendorMozilla Affected before 68.9.0 Fixed in 68.9.0 Patch available CNA
- Firefox VendorMozilla Affected before 77 Fixed in 77 Patch available CNA
- Firefox ESR VendorMozilla Affected before 68.9 Fixed in 68.9 Patch available CNA
CPE configurations NVD · 7
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | before 77.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* | before 68.9.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | before 68.9.0 | 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 77.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 68.9.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 68.9.0 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 Thunderbird (Mozilla) Fixed in 68.9.0
- Fix · CNA Firefox (Mozilla) Fixed in 77
- Fix · CNA Firefox ESR (Mozilla) Fixed in 68.9
Red Hat 10 advisories
- RHSA-2020:2615 Released 2020-06-22 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Client (v. 7) thunderbird-68.9.0-1.el7_8
- Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-68.9.0-1.el7_8
- Red Hat Enterprise Linux Workstation (v. 7) thunderbird-68.9.0-1.el7_8
- RHSA-2020:2614 Released 2020-06-22 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-68.9.0-1.el8_2
- RHSA-2020:2613 Released 2020-06-19 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Desktop (v. 6) thunderbird-68.9.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) thunderbird-68.9.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) thunderbird-68.9.0-1.el6_10
Show 7 more Red Hat advisories
- RHSA-2020:2611 Released 2020-06-19 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-68.9.0-1.el8_1
- RHSA-2020:2616 Released 2020-06-19 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird-68.9.0-1.el8_0
- RHSA-2020:2381 Released 2020-06-03 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Client (v. 7) firefox-68.9.0-1.el7_8
- Red Hat Enterprise Linux Client Optional (v. 7) firefox-68.9.0-1.el7_8
- Red Hat Enterprise Linux Server (v. 7) firefox-68.9.0-1.el7_8
- Red Hat Enterprise Linux Server Optional (v. 7) firefox-68.9.0-1.el7_8
- Red Hat Enterprise Linux Workstation (v. 7) firefox-68.9.0-1.el7_8
- Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-68.9.0-1.el7_8
- RHSA-2020:2382 Released 2020-06-03 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-68.9.0-1.el8_0
- RHSA-2020:2378 Released 2020-06-03 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Desktop (v. 6) firefox-68.9.0-1.el6_10
- Red Hat Enterprise Linux Desktop Optional (v. 6) firefox-68.9.0-1.el6_10
- Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox-68.9.0-1.el6_10
- Red Hat Enterprise Linux Server (v. 6) firefox-68.9.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) firefox-68.9.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) firefox-68.9.0-1.el6_10
- Red Hat Enterprise Linux Workstation Optional (v. 6) firefox-68.9.0-1.el6_10
- RHSA-2020:2380 Released 2020-06-03 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-68.9.0-1.el8_1
- RHSA-2020:2379 Released 2020-06-03 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-68.9.0-1.el8_2
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-4421-1
10 records Highest priority Priority MEDIUM 5 MEDIUM, 5 LOW
Other records, highest priority first
- TI-2020-09937 Use after free in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
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-2020:2379, RHSA-2020:2614 |
| Red Hat Enterprise Linux AppStream E4S (v. 8.0) | Fixed | RHSA-2020:2382, RHSA-2020:2616 |
| Red Hat Enterprise Linux AppStream EUS (v. 8.1) | Fixed | RHSA-2020:2380, RHSA-2020:2611 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2020:2381, RHSA-2020:2615 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2020:2381 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2020:2378, RHSA-2020:2613 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2020:2378 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2020:2378 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2020:2378 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2020:2381 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2020:2378, RHSA-2020:2613 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2020:2381, RHSA-2020:2615 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2020:2378, RHSA-2020:2613 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2020:2381, RHSA-2020:2615 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2020:2378 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2020:2381 |
Timeline
- 2026-10-02 Threatist record created from CVE-2020-12405
- 2026-10-03 Alias added: GHSA-7768-mfm4-9cmv
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-2020-12405 · CVE Program
- CVE-2020-12405 · NVD
- FIRST EPSS
- GHSA-7768-mfm4-9cmv · GitHub Advisory Database · CC BY 4.0
- CVE-2020-12405 · Red Hat security data · CC BY 4.0
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