Improper check for unusual conditions in Mozilla Firefox
Priority LOW 39CWE-754Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Partial Red Hat: 16 fixed, 3 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
Incorrect boundary conditions in the Libraries component in NSS. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0039 33rd percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 115.35, 140.10, 150Thunderbird (Mozilla): 140.10, 150Red Hat: 27 advisoriesRed Hat: 16 fixed, 3 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- 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 | — | 115.35, 140.10, 150 | Patch available | CNA |
| Mozilla | Thunderbird | — | 140.10, 150 | Patch available | CNA |
- Firefox VendorMozilla Affected — Fixed in 115.35, 140.10, 150 Patch available CNA
- Thunderbird VendorMozilla Affected — Fixed in 140.10, 150 Patch available CNA
CPE configurations NVD · 4
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* | before 115.35.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* | before 150.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* | 140.0 to before 140.10.0 | Vulnerable | Mozilla |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:* | before 140.10.0 | Vulnerable | Mozilla |
- cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* Versions before 115.35.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* Versions before 150.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* Versions 140.0 to before 140.10.0 Vulnerable ·Mozilla
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:* Versions before 140.10.0 Vulnerable ·Mozilla
Remediation
- Fix · CNA Firefox (Mozilla) Fixed in 115.35, 140.10, 150
- Fix · CNA Thunderbird (Mozilla) Fixed in 140.10, 150
Red Hat 27 advisories
- RHSA-2026:19704 Released 2026-05-20 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux Server (v. 7 ELS) firefox-140.10.0-2.el7_9
- RHSA-2026:19655 Released 2026-05-20 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox-140.10.0-1.el8_4
- Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) firefox-140.10.0-1.el8_4
- RHSA-2026:19542 Released 2026-05-20 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream AUS (v.8.6) firefox-140.10.0-1.el8_6
- Red Hat Enterprise Linux AppStream E4S (v.8.6) firefox-140.10.0-1.el8_6
- Red Hat Enterprise Linux AppStream TUS (v.8.6) firefox-140.10.0-1.el8_6
Show 24 more Red Hat advisories
- RHSA-2026:19462 Released 2026-05-20 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v.9.6) thunderbird-140.10.0-1.el9_6
- RHSA-2026:19464 Released 2026-05-20 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v.9.4) firefox-140.10.0-1.el9_4, firefox-x11-140.10.0-1.el9_4
- RHSA-2026:19466 Released 2026-05-20 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream AUS (v.8.6) thunderbird-140.10.0-1.el8_6
- Red Hat Enterprise Linux AppStream E4S (v.8.6) thunderbird-140.10.0-1.el8_6
- Red Hat Enterprise Linux AppStream TUS (v.8.6) thunderbird-140.10.0-1.el8_6
- RHSA-2026:19469 Released 2026-05-20 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v.9.4) thunderbird-140.10.0-1.el9_4
- RHSA-2026:19467 Released 2026-05-20 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v.8.8) thunderbird-140.10.0-1.el8_8
- Red Hat Enterprise Linux AppStream TUS (v.8.8) thunderbird-140.10.0-1.el8_8
- RHSA-2026:19468 Released 2026-05-20 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v.9.0) thunderbird-140.10.0-1.el9_0
- RHSA-2026:19463 Released 2026-05-20 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream EUS (v. 10.0) thunderbird-140.10.0-1.el10_0
- RHSA-2026:19465 Released 2026-05-20 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream AUS (v.8.4) thunderbird-140.10.0-1.el8_4
- Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) thunderbird-140.10.0-1.el8_4
- RHSA-2026:19461 Released 2026-05-20 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream E4S (v.9.2) thunderbird-140.10.0-1.el9_2
- RHSA-2026:19348 Released 2026-05-19 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 9) thunderbird-140.10.1-1.el9_8
- RHSA-2026:19201 Released 2026-05-19 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 9) firefox-140.10.0-1.el9_8, firefox-x11-140.10.0-1.el9_8
- RHSA-2026:19131 Released 2026-05-19 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 10) thunderbird-140.10.0-1.el10_2
- RHSA-2026:19041 Released 2026-05-19 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 10) firefox-140.10.0-1.el10_2
- RHSA-2026:17688 Released 2026-05-14 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v.9.6) firefox-140.10.0-1.el9_6, firefox-x11-140.10.0-1.el9_6
- RHSA-2026:17689 Released 2026-05-14 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v.9.2) firefox-140.10.0-1.el9_2, firefox-x11-140.10.0-1.el9_2
- RHSA-2026:17687 Released 2026-05-14 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v.9.0) firefox-140.10.0-1.el9_0
- RHSA-2026:17690 Released 2026-05-14 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream EUS (v. 10.0) firefox-140.10.0-1.el10_0
- RHSA-2026:17477 Released 2026-05-14 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream E4S (v.8.8) firefox-140.10.0-1.el8_8
- Red Hat Enterprise Linux AppStream TUS (v.8.8) firefox-140.10.0-1.el8_8
- RHSA-2026:15892 Released 2026-05-11 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 9) thunderbird-140.10.0-1.el9_7
- RHSA-2026:13537 Released 2026-05-04 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 8) thunderbird-140.10.0-1.el8_10
- RHSA-2026:12285 Released 2026-04-30 · Red Hat rating Importantthunderbird security update
- Red Hat Enterprise Linux AppStream (v. 10) thunderbird-140.10.0-1.el10_1
- RHSA-2026:10766 Released 2026-04-27 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 8) firefox-140.10.0-1.el8_10
- RHSA-2026:10767 Released 2026-04-27 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 10) firefox-140.10.0-1.el10_1
- RHSA-2026:10757 Released 2026-04-27 · Red Hat rating Importantfirefox security update
- Red Hat Enterprise Linux AppStream (v. 9) firefox-140.10.0-1.el9_7, firefox-x11-140.10.0-1.el9_7
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 | No fix yet |
| 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-2026:10767, RHSA-2026:12285, RHSA-2026:19041, RHSA-2026:19131 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:10766, RHSA-2026:13537 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:10757, RHSA-2026:15892, RHSA-2026:19201, RHSA-2026:19348 |
| Red Hat Enterprise Linux AppStream AUS (v.8.4) | Fixed | RHSA-2026:19465, RHSA-2026:19655 |
| Red Hat Enterprise Linux AppStream AUS (v.8.6) | Fixed | RHSA-2026:19466, RHSA-2026:19542 |
| Red Hat Enterprise Linux AppStream E4S (v.8.6) | Fixed | RHSA-2026:19466, RHSA-2026:19542 |
| Red Hat Enterprise Linux AppStream E4S (v.8.8) | Fixed | RHSA-2026:17477, RHSA-2026:19467 |
| Red Hat Enterprise Linux AppStream E4S (v.9.0) | Fixed | RHSA-2026:17687, RHSA-2026:19468 |
| Red Hat Enterprise Linux AppStream E4S (v.9.2) | Fixed | RHSA-2026:17689, RHSA-2026:19461 |
| Red Hat Enterprise Linux AppStream EUS (v. 10.0) | Fixed | RHSA-2026:17690, RHSA-2026:19463 |
| Red Hat Enterprise Linux AppStream EUS (v.9.4) | Fixed | RHSA-2026:19464, RHSA-2026:19469 |
| Red Hat Enterprise Linux AppStream EUS (v.9.6) | Fixed | RHSA-2026:17688, RHSA-2026:19462 |
| Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) | Fixed | RHSA-2026:19465, RHSA-2026:19655 |
| Red Hat Enterprise Linux AppStream TUS (v.8.6) | Fixed | RHSA-2026:19466, RHSA-2026:19542 |
| Red Hat Enterprise Linux AppStream TUS (v.8.8) | Fixed | RHSA-2026:17477, RHSA-2026:19467 |
| Red Hat Enterprise Linux Server (v. 7 ELS) | Fixed | RHSA-2026:19704 |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-6772
- 2026-10-03 Alias added: GHSA-c2q7-642g-3vwr
References
Advisory 5
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-2026-6772 · CVE Program
- CVE-2026-6772 · NVD
- FIRST EPSS
- GHSA-c2q7-642g-3vwr · GitHub Advisory Database · CC BY 4.0
- CVE-2026-6772 · 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