Use after free in Mozilla Firefox
Priority MEDIUM 46CWE-416Published · 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
- Fixed
Attack profile from CVSS 3.0 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
Summary
A use-after-free vulnerability can occur in the Fetch API when the worker or the associated window are freed when still in use, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.
Why it matters now
EPSS 0.02267 83rd percentileScored 2026-11-07
Fix Fixed Firefox (Mozilla): 56Firefox ESR (Mozilla): 52.4+1 more productRed Hat: 2 advisories
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 56 | 56 | Patch available | CNA |
| Mozilla | Firefox ESR | before 52.4 | 52.4 | Patch available | CNA |
| Mozilla | Thunderbird | before 52.4 | 52.4 | Patch available | CNA |
- Firefox VendorMozilla Affected before 56 Fixed in 56 Patch available CNA
- Firefox ESR VendorMozilla Affected before 52.4 Fixed in 52.4 Patch available CNA
- Thunderbird VendorMozilla Affected before 52.4 Fixed in 52.4 Patch available CNA
CPE configurations NVD · 22
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
| cpe:2.3:o:redhat:enterprise_linux:5.0:*:*:*:*:*:*:* | 5.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:* | 6.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_desktop:5.0:*:*:*:*:*:*:* | 5.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:* | 6.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server:5.0:*:*:*:*:*:*:* | 5.0 | Vulnerable | Red Hat |
- cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Debian
- cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Debian
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
- cpe:2.3:o:redhat:enterprise_linux:5.0:*:*:*:*:*:*:* Versions 5.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:* Versions 6.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_desktop:5.0:*:*:*:*:*:*:* Versions 5.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:* Versions 6.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server:5.0:*:*:*:*:*:*:* Versions 5.0 Vulnerable ·Red Hat
Show 12 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:* | 6.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server_aus:7.3:*:*:*:*:*:*:* | 7.3 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:* | 7.4 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server_eus:7.3:*:*:*:*:*:*:* | 7.3 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server_eus:7.4:*:*:*:*:*:*:* | 7.4 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server_eus:7.5:*:*:*:*:*:*:* | 7.5 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_workstation:5.0:*:*:*:*:*:*:* | 5.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:* | 6.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | before 52.4.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | before 56.0; before 52.4.0 | Vulnerable | Mozilla |
- cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:* Versions 6.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server_aus:7.3:*:*:*:*:*:*:* Versions 7.3 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:* Versions 7.4 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server_eus:7.3:*:*:*:*:*:*:* Versions 7.3 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server_eus:7.4:*:*:*:*:*:*:* Versions 7.4 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server_eus:7.5:*:*:*:*:*:*:* Versions 7.5 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_workstation:5.0:*:*:*:*:*:*:* Versions 5.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:* Versions 6.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 52.4.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 56.0; before 52.4.0 Vulnerable ·Mozilla
Remediation
- Fix · CNA Firefox (Mozilla) Fixed in 56
- Fix · CNA Firefox ESR (Mozilla) Fixed in 52.4
- Fix · CNA Thunderbird (Mozilla) Fixed in 52.4
Red Hat 2 advisories
- RHSA-2017:2885 Released 2017-10-11 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Client (v. 7) thunderbird-52.4.0-2.el7_4
- Red Hat Enterprise Linux Desktop (v. 6) thunderbird-52.4.0-2.el6_9
- Red Hat Enterprise Linux Server Optional (v. 6) thunderbird-52.4.0-2.el6_9
- Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-52.4.0-2.el7_4
- Red Hat Enterprise Linux Workstation (v. 6) thunderbird-52.4.0-2.el6_9
- Red Hat Enterprise Linux Workstation (v. 7) thunderbird-52.4.0-2.el7_4
- RHSA-2017:2831 Released 2017-09-28 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux Client (v. 7) firefox-52.4.0-1.el7_4
- Red Hat Enterprise Linux Client Optional (v. 7) firefox-52.4.0-1.el7_4
- Red Hat Enterprise Linux Desktop (v. 6) firefox-52.4.0-1.el6_9
- Red Hat Enterprise Linux Desktop Optional (v. 6) firefox-52.4.0-1.el6_9
- Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox-52.4.0-1.el6_9
- Red Hat Enterprise Linux Server (v. 6) firefox-52.4.0-1.el6_9
- Red Hat Enterprise Linux Server (v. 7) firefox-52.4.0-1.el7_4
- Red Hat Enterprise Linux Server Optional (v. 6) firefox-52.4.0-1.el6_9, firefox-52.4.0-1.el6_9.ppc
- Red Hat Enterprise Linux Server Optional (v. 7) firefox-52.4.0-1.el7_4, firefox-52.4.0-1.el7_4.ppc
- Red Hat Enterprise Linux Workstation (v. 6) firefox-52.4.0-1.el6_9
- Red Hat Enterprise Linux Workstation (v. 7) firefox-52.4.0-1.el7_4
- Red Hat Enterprise Linux Workstation Optional (v. 6) firefox-52.4.0-1.el6_9
- Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-52.4.0-1.el7_4
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 — GLSA-201803-14
21 records Highest priority Priority MEDIUM 13 MEDIUM, 8 LOW
Other records, highest priority first
- TI-2017-05404 Memory corruption in Mozilla ThunderbirdPriority MEDIUM 49
- TI-2017-05403 Memory corruption in Mozilla ThunderbirdPriority MEDIUM 49
- TI-2017-05441 Memory corruption in Mozilla FirefoxPriority MEDIUM 48
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — DSA-3987
8 records Highest priority Priority MEDIUM 5 MEDIUM, 3 LOW
Other records, highest priority first
- TI-2017-05441 Memory corruption in Mozilla FirefoxPriority MEDIUM 48
- TI-2017-05436 Use after free in Mozilla FirefoxPriority MEDIUM 48
- TI-2017-05435 Use after free in Mozilla FirefoxPriority MEDIUM 48
Show 3 more groups
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — DSA-4014
8 records Highest priority Priority MEDIUM 5 MEDIUM, 3 LOW
Other records, highest priority first
- TI-2017-05441 Memory corruption in Mozilla FirefoxPriority MEDIUM 48
- TI-2017-05436 Use after free in Mozilla FirefoxPriority MEDIUM 48
- TI-2017-05435 Use after free in Mozilla FirefoxPriority MEDIUM 48
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — RHSA-2017:2831
7 records Highest priority Priority MEDIUM 5 MEDIUM, 2 LOW
Other records, highest priority first
- TI-2017-05441 Memory corruption in Mozilla FirefoxPriority MEDIUM 48
- TI-2017-05436 Use after free in Mozilla FirefoxPriority MEDIUM 48
- TI-2017-05435 Use after free in Mozilla FirefoxPriority MEDIUM 48
- Advisory ·
Mozilla Firefox, Firefox ESR, Thunderbird — RHSA-2017:2885
7 records Highest priority Priority MEDIUM 5 MEDIUM, 2 LOW
Other records, highest priority first
- TI-2017-05441 Memory corruption in Mozilla FirefoxPriority MEDIUM 48
- TI-2017-05436 Use after free in Mozilla FirefoxPriority MEDIUM 48
- TI-2017-05435 Use after free in Mozilla FirefoxPriority MEDIUM 48
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2017:2831, RHSA-2017:2885 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2017:2831 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2017:2831, RHSA-2017:2885 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2017:2831 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2017:2831 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2017:2831 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2017:2831 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2017:2831, RHSA-2017:2885 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2017:2831, RHSA-2017:2885 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2017:2831, RHSA-2017:2885 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2017:2831, RHSA-2017:2885 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2017:2831 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2017:2831 |
Timeline
- 2026-10-02 Threatist record created from CVE-2017-7793
- 2026-10-03 Alias added: GHSA-56mj-fm7c-959m
References
Advisory 9
- [debian-lts-announce] 20171101 [SECURITY] [DLA 1153-1] icedove/thunderbird security update
- https://www.mozilla.org/security/advisories/mfsa2017-22/
- RHSA-2017:2831
- RHSA-2017:2885
- https://www.mozilla.org/security/advisories/mfsa2017-21/
- DSA-4014
- https://www.mozilla.org/security/advisories/mfsa2017-23/
- DSA-3987
- GLSA-201803-14
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-2017-7793 · CVE Program
- CVE-2017-7793 · NVD
- FIRST EPSS
- GHSA-56mj-fm7c-959m · GitHub Advisory Database · CC BY 4.0
- CVE-2017-7793 · Red Hat security data · CC BY 4.0
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