CVE-2026-84126 — MEDIUM (4.3)

Q: What is CVE-2026-84126?

CVE-2026-84126 is a vulnerability with a CVSS score of 4.3 (MEDIUM). Incorrect boundary conditions in the Layout: Grid component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.

Q: How severe is CVE-2026-84126?

CVE-2026-84126 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2026-84126?

Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird.

Vulnerability Description

Incorrect boundary conditions in the Layout: Grid component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.

CVSS Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality

LOW

Integrity

NONE

Availability

NONE

Affected Products

Vendor	Product	Versions
Mozilla	Firefox	< 155.0.0
Mozilla	Thunderbird	< 155.0

Related Weaknesses (CWE)

CWE-120

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2063893Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-82/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-86/Vendor Advisory

FAQ

What is CVE-2026-84126?

CVE-2026-84126 is a vulnerability with a CVSS score of 4.3 (MEDIUM). Incorrect boundary conditions in the Layout: Grid component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.

How severe is CVE-2026-84126?

CVE-2026-84126 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-84126?

Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird.