CVE-2026-2776 | Sandbox escape due to incorrect boundary conditions in the T… | CVSS 10.0 CRITICAL

Description

Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Metadata

CVE ID: CVE-2026-2776
State: PUBLISHED
Assigner: mozilla
Reserved: 2026-02-19 15:06 UTC
Published: 2026-02-24 13:33 UTC
Last updated: 2026-07-15 01:13 UTC
Primary CWE: CWE-119
CWE-119 Improper Restriction of Operations within the Bounds…
Vendor / Product: Mozilla / Firefox
Sources: cve.org · NVD

Severity & Metrics

10.0 CRITICAL CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: yes
Tech. Impact: total

Affected products (2)

Vendor	Product	Platform	Versions
Mozilla	Firefox	—	115.33 ≤ 115., 140.8 ≤ 140., 148 ≤ *
Mozilla	Thunderbird	—	140.8 ≤ 140., 148 ≤

Weakness (CWE)

CWE	Source	Description
CWE-119	adp	CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS scores (2)

Score	Severity	Version	Source	Vector
10.0	CRITICAL	3.1	adp	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
7.5	HIGH	3.1	adp	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

References (6)