Out-of-bounds write in Mozilla Firefox
Priority MEDIUM 43CWE-787Published · 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-787 and the CVSS impact.
Summary
Mozilla developers and community members reported memory safety bugs present in Firefox 78 and Firefox ESR 78.0. 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 < 79, Firefox ESR < 68.11, Firefox ESR < 78.1, Thunderbird < 68.11, and Thunderbird < 78.1.
Why it matters now
EPSS 0.02391 84th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 79Firefox ESR (Mozilla): 68.11, 78.1+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 | before 79 | 79 | Patch available | CNA |
| Mozilla | Firefox ESR | before 68.11; before 78.1 | 68.11, 78.1 | Patch available | CNA |
| Mozilla | Thunderbird | before 68.11; before 78.1 | 68.11, 78.1 | Patch available | CNA |
- Firefox VendorMozilla Affected before 79 Fixed in 79 Patch available CNA
- Firefox ESR VendorMozilla Affected before 68.11; before 78.1 Fixed in 68.11, 78.1 Patch available CNA
- Thunderbird VendorMozilla Affected before 68.11; before 78.1 Fixed in 68.11, 78.1 Patch available CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | before 79.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* | before 68.11; 78.0 to before 78.1.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | before 68.11; 78.0.1 to before 78.1.0 | Vulnerable | Mozilla |
| 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:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* | 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:20.04:*:*:*:lts:*:*:* | 20.04 | Vulnerable | Canonical |
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 79.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 68.11; 78.0 to before 78.1.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 68.11; 78.0.1 to before 78.1.0 Vulnerable ·Mozilla
- 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
- cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* 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:20.04:*:*:*:lts:*:*:* Versions 20.04 Vulnerable ·Canonical
Remediation
- Fix · CNA Firefox (Mozilla) Fixed in 79
- Fix · CNA Firefox ESR (Mozilla) Fixed in 68.11, 78.1
- Fix · CNA Thunderbird (Mozilla) Fixed in 68.11, 78.1
Red Hat 10 advisories
- RHSA-2020:3345 Released 2020-08-06 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Desktop (v. 6) thunderbird-68.11.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) thunderbird-68.11.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) thunderbird-68.11.0-1.el6_10
- RHSA-2020:3344 Released 2020-08-06 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Client (v. 7) thunderbird-68.11.0-1.el7_8
- Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-68.11.0-1.el7_8
- Red Hat Enterprise Linux Workstation (v. 7) thunderbird-68.11.0-1.el7_8
- RHSA-2020:3341 Released 2020-08-06 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-68.11.0-1.el8_2
Show 7 more Red Hat advisories
- RHSA-2020:3342 Released 2020-08-06 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-68.11.0-1.el8_1
- RHSA-2020:3343 Released 2020-08-06 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird-68.11.0-1.el8_0
- RHSA-2020:3253 Released 2020-07-30 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Client (v. 7) firefox-68.11.0-1.el7_8
- Red Hat Enterprise Linux Client Optional (v. 7) firefox-68.11.0-1.el7_8
- Red Hat Enterprise Linux Server (v. 7) firefox-68.11.0-1.el7_8
- Red Hat Enterprise Linux Server Optional (v. 7) firefox-68.11.0-1.el7_8
- Red Hat Enterprise Linux Workstation (v. 7) firefox-68.11.0-1.el7_8
- Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-68.11.0-1.el7_8
- RHSA-2020:3254 Released 2020-07-30 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-68.11.0-1.el8_1
- RHSA-2020:3241 Released 2020-07-30 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-68.11.0-1.el8_2
- RHSA-2020:3233 Released 2020-07-29 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Desktop (v. 6) firefox-68.11.0-1.el6_10
- Red Hat Enterprise Linux Desktop Optional (v. 6) firefox-68.11.0-1.el6_10
- Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox-68.11.0-1.el6_10
- Red Hat Enterprise Linux Server (v. 6) firefox-68.11.0-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) firefox-68.11.0-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) firefox-68.11.0-1.el6_10
- Red Hat Enterprise Linux Workstation Optional (v. 6) firefox-68.11.0-1.el6_10
- RHSA-2020:3229 Released 2020-07-29 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-68.11.0-1.el8_0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Mozilla Firefox 79
8 records Highest priority Priority MEDIUM 2 MEDIUM, 6 LOW
Other records, highest priority first
- TI-2020-12331 Type confusion in Mozilla Firefox ESRPriority MEDIUM 41
- TI-2020-12332 Uncontrolled search path in Mozilla Firefox ESRPriority LOW 34
- TI-2020-12333 Improper check for unusual conditions in Mozilla Firefox ESRPriority LOW 32
- Release ·
Mozilla Firefox ESR, Thunderbird 68.11, 78.1
2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW
Other records, highest priority first
- TI-2020-12327 Origin validation error in Mozilla FirefoxPriority LOW 31
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-2020:3241, RHSA-2020:3341 |
| Red Hat Enterprise Linux AppStream E4S (v. 8.0) | Fixed | RHSA-2020:3229, RHSA-2020:3343 |
| Red Hat Enterprise Linux AppStream EUS (v. 8.1) | Fixed | RHSA-2020:3254, RHSA-2020:3342 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2020:3253, RHSA-2020:3344 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2020:3253 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2020:3233, RHSA-2020:3345 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2020:3233 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2020:3233 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2020:3233 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2020:3253 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2020:3233, RHSA-2020:3345 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2020:3253, RHSA-2020:3344 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2020:3233, RHSA-2020:3345 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2020:3253, RHSA-2020:3344 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2020:3233 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2020:3253 |
Timeline
- 2026-10-02 Threatist record created from CVE-2020-15659
- 2026-10-03 Alias added: GHSA-r2p6-cvv5-qcq5
References
Advisory 6
- https://www.mozilla.org/security/advisories/mfsa2020-30/
- https://www.mozilla.org/security/advisories/mfsa2020-35/
- https://www.mozilla.org/security/advisories/mfsa2020-32/
- https://www.mozilla.org/security/advisories/mfsa2020-33/
- https://www.mozilla.org/security/advisories/mfsa2020-31/
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=1550133%2C1633880%2C1643613%2C1644839%2C1645835%2C1646006%2C1646787%2C1649347%2C1650811%2C1651678
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-2020-15659 · CVE Program
- CVE-2020-15659 · NVD
- FIRST EPSS
- GHSA-r2p6-cvv5-qcq5 · GitHub Advisory Database · CC BY 4.0
- CVE-2020-15659 · 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