Information disclosure in Mozilla Firefox
Priority LOW 20CWE-200Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Partial Red Hat: 14 fixed, 3 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-200.
Summary
Information disclosure in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00324 25th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 140.14, 153.1, 154Thunderbird (Mozilla): 140.14, 153.1, 154Red Hat: 21 advisoriesRed Hat: 14 fixed, 3 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
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 | — | 140.14, 153.1, 154 | Patch available | CNA |
| Mozilla | Thunderbird | — | 140.14, 153.1, 154 | Patch available | CNA |
Remediation
- Fix · CNA Firefox (Mozilla) Fixed in 140.14, 153.1, 154
- Fix · CNA Thunderbird (Mozilla) Fixed in 140.14, 153.1, 154
Red Hat 21 advisories
- RHSA-2026:65888 Released 2026-09-09 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v.9.2) firefox-140.14.0-1.el9_2, firefox-x11-140.14.0-1.el9_2
- RHSA-2026:65766 Released 2026-09-09 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v.9.2) thunderbird-140.14.0-1.el9_2
- RHSA-2026:65765 Released 2026-09-09 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v.8.8) thunderbird-140.14.0-1.el8_8
- Red Hat Enterprise Linux AppStream TUS (v.8.8) thunderbird-140.14.0-1.el8_8
Show 18 more Red Hat advisories
- RHSA-2026:65757 Released 2026-09-09 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream AUS (v.8.6) thunderbird-140.14.0-1.el8_6
- Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) thunderbird-140.14.0-1.el8_6
- RHSA-2026:65764 Released 2026-09-09 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream AUS (v.8.4) thunderbird-140.14.0-1.el8_4
- Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) thunderbird-140.14.0-1.el8_4
- RHSA-2026:65670 Released 2026-09-08 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v.9.6) thunderbird-140.14.0-1.el9_6
- RHSA-2026:65669 Released 2026-09-08 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v.9.4) thunderbird-140.14.0-1.el9_4
- RHSA-2026:65633 Released 2026-09-08 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v. 10.0) thunderbird-140.14.0-1.el10_0
- RHSA-2026:65442 Released 2026-09-08 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Server (v. 7 ELS) firefox-140.14.0-1.el7_9
- RHSA-2026:65158 Released 2026-09-08 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 9) thunderbird-140.14.0-1.el9_8
- RHSA-2026:65159 Released 2026-09-08 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 10) thunderbird-140.14.0-1.el10_2
- RHSA-2026:65160 Released 2026-09-08 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-140.14.0-1.el8_10
- RHSA-2026:65103 Released 2026-09-08 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v.9.6) firefox-140.14.0-1.el9_6, firefox-x11-140.14.0-1.el9_6
- RHSA-2026:65105 Released 2026-09-08 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v.9.4) firefox-140.14.0-1.el9_4, firefox-x11-140.14.0-1.el9_4
- RHSA-2026:65111 Released 2026-09-08 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox-140.14.0-1.el8_4
- Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) firefox-140.14.0-1.el8_4
- RHSA-2026:65110 Released 2026-09-08 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream AUS (v.8.6) firefox-140.14.0-1.el8_6
- Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) firefox-140.14.0-1.el8_6
- RHSA-2026:64813 Released 2026-09-08 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v. 10.0) firefox-140.14.0-1.el10_0
- RHSA-2026:64814 Released 2026-09-08 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v.8.8) firefox-140.14.0-1.el8_8
- Red Hat Enterprise Linux AppStream TUS (v.8.8) firefox-140.14.0-1.el8_8
- RHSA-2026:58897 Released 2026-08-24 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 9) firefox-140.14.0-1.el9_8, firefox-x11-140.14.0-1.el9_8
- RHSA-2026:58899 Released 2026-08-24 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 10) firefox-140.14.0-1.el10_2
- RHSA-2026:58898 Released 2026-08-24 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-140.14.0-1.el8_10
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | — |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:58899, RHSA-2026:65159 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:58898, RHSA-2026:65160 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:58897, RHSA-2026:65158 |
| Red Hat Enterprise Linux AppStream AUS (v.8.4) | Fixed | RHSA-2026:65111, RHSA-2026:65764 |
| Red Hat Enterprise Linux AppStream AUS (v.8.6) | Fixed | RHSA-2026:65110, RHSA-2026:65757 |
| Red Hat Enterprise Linux AppStream E4S (v.8.8) | Fixed | RHSA-2026:64814, RHSA-2026:65765 |
| Red Hat Enterprise Linux AppStream E4S (v.9.2) | Fixed | RHSA-2026:65766, RHSA-2026:65888 |
| Red Hat Enterprise Linux AppStream E4S (v.9.4) | Fixed | RHSA-2026:65105, RHSA-2026:65669 |
| Red Hat Enterprise Linux AppStream EUS (v. 10.0) | Fixed | RHSA-2026:64813, RHSA-2026:65633 |
| Red Hat Enterprise Linux AppStream EUS (v.9.6) | Fixed | RHSA-2026:65103, RHSA-2026:65670 |
| Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) | Fixed | RHSA-2026:65111, RHSA-2026:65764 |
| Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) | Fixed | RHSA-2026:65110, RHSA-2026:65757 |
| Red Hat Enterprise Linux AppStream TUS (v.8.8) | Fixed | RHSA-2026:64814, RHSA-2026:65765 |
| Red Hat Enterprise Linux Server (v. 7 ELS) | Fixed | RHSA-2026:65442 |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74971
- 2026-10-03 Alias added: GHSA-67f4-mqxj-f332
References
Advisory 6
- https://www.mozilla.org/security/advisories/mfsa2026-74/
- https://www.mozilla.org/security/advisories/mfsa2026-76/
- https://www.mozilla.org/security/advisories/mfsa2026-77/
- https://www.mozilla.org/security/advisories/mfsa2026-78/
- https://www.mozilla.org/security/advisories/mfsa2026-79/
- https://www.mozilla.org/security/advisories/mfsa2026-80/
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-2026-74971 · CVE Program
- CVE-2026-74971 · NVD
- FIRST EPSS
- GHSA-67f4-mqxj-f332 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74971 · 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