Type confusion in Mozilla Firefox ESR
Priority CRITICAL 97Exploited in the wildCWE-843Published · 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 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-843 and the CVSS impact.
Summary
Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.
Why it matters now
Exploitation Active In CISA KEV since 2021-11-03CISA due date 2022-05-03
EPSS 0.46311 98th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Firefox ESR (Mozilla): 68.4.1Thunderbird (Mozilla): 68.4.1+1 more productRed Hat: 8 advisoriesRed Hat: 15 fixed, 1 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Active
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mozilla | Firefox ESR | before 68.4.1 | 68.4.1 | Patch available | CNA |
| Mozilla | Thunderbird | before 68.4.1 | 68.4.1 | Patch available | CNA |
| Mozilla | Firefox | before 72.0.1 | 72.0.1 | Patch available | CNA |
- Firefox ESR VendorMozilla Affected before 68.4.1 Fixed in 68.4.1 Patch available CNA
- Thunderbird VendorMozilla Affected before 68.4.1 Fixed in 68.4.1 Patch available CNA
- Firefox VendorMozilla Affected before 72.0.1 Fixed in 72.0.1 Patch available CNA
CPE configurations NVD · 4
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* | before 68.4.1 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* | before 72.0.1 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | before 68.4.1 | Vulnerable | Mozilla |
| cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:* | 16.04 | Vulnerable | Canonical |
- cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* Versions before 68.4.1 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* Versions before 72.0.1 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 68.4.1 Vulnerable ·Mozilla
- cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:* Versions 16.04 Vulnerable ·Canonical
Remediation
- Fix · CNA Firefox ESR (Mozilla) Fixed in 68.4.1
- Fix · CNA Thunderbird (Mozilla) Fixed in 68.4.1
- Fix · CNA Firefox (Mozilla) Fixed in 72.0.1
Red Hat 8 advisories
- RHSA-2020:0295 Released 2020-01-30 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-68.4.1-1.el8_0
- RHSA-2020:0292 Released 2020-01-30 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird-68.4.1-2.el8_0
- RHSA-2020:0127 Released 2020-01-16 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-68.4.1-2.el8_1
Show 5 more Red Hat advisories
- RHSA-2020:0120 Released 2020-01-16 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Client (v. 7) thunderbird-68.4.1-2.el7_7
- Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-68.4.1-2.el7_7
- Red Hat Enterprise Linux Workstation (v. 7) thunderbird-68.4.1-2.el7_7
- RHSA-2020:0123 Released 2020-01-16 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux Desktop (v. 6) thunderbird-68.4.1-2.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) thunderbird-68.4.1-2.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) thunderbird-68.4.1-2.el6_10
- RHSA-2020:0111 Released 2020-01-14 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-68.4.1-1.el8_1
- RHSA-2020:0085 Released 2020-01-13 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux Client (v. 7) firefox-68.4.1-1.el7_7
- Red Hat Enterprise Linux Client Optional (v. 7) firefox-68.4.1-1.el7_7
- Red Hat Enterprise Linux Server (v. 7) firefox-68.4.1-1.el7_7
- Red Hat Enterprise Linux Server Optional (v. 7) firefox-68.4.1-1.el7_7
- Red Hat Enterprise Linux Workstation (v. 7) firefox-68.4.1-1.el7_7
- Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-68.4.1-1.el7_7
- RHSA-2020:0086 Released 2020-01-13 · Red Hat rating Criticalfirefox security update
- Red Hat Enterprise Linux Desktop (v. 6) firefox-68.4.1-1.el6_10
- Red Hat Enterprise Linux Desktop Optional (v. 6) firefox-68.4.1-1.el6_10
- Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox-68.4.1-1.el6_10
- Red Hat Enterprise Linux Server (v. 6) firefox-68.4.1-1.el6_10
- Red Hat Enterprise Linux Server Optional (v. 6) firefox-68.4.1-1.el6_10
- Red Hat Enterprise Linux Workstation (v. 6) firefox-68.4.1-1.el6_10
- Red Hat Enterprise Linux Workstation Optional (v. 6) firefox-68.4.1-1.el6_10
Vendor assessments
Red Hat
Red Hat rating: Critical. 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-2020:0111, RHSA-2020:0127 |
| Red Hat Enterprise Linux AppStream E4S (v. 8.0) | Fixed | RHSA-2020:0292, RHSA-2020:0295 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2020:0085, RHSA-2020:0120 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2020:0085 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2020:0086, RHSA-2020:0123 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2020:0086 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2020:0086 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2020:0086 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2020:0085 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2020:0086, RHSA-2020:0123 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2020:0085, RHSA-2020:0120 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2020:0086, RHSA-2020:0123 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2020:0085, RHSA-2020:0120 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2020:0086 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2020:0085 |
Timeline
- 2021-11-03 Added to CISA KEV
- 2026-10-02 Threatist record created from CVE-2019-17026
- 2026-10-03 Alias added: GHSA-9m3f-27xq-x4j5
References
Advisory 4
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-2019-17026 · CVE Program
- CVE-2019-17026 · NVD
- CISA Known Exploited Vulnerabilities
- FIRST EPSS
- GHSA-9m3f-27xq-x4j5 · GitHub Advisory Database · CC BY 4.0
- CVE-2019-17026 · Red Hat security data · CC BY 4.0
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