Is CVE-2026-2776 actively exploited?

No active exploitation of CVE-2026-2776 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-2776 be exploited remotely?

Yes. CVE-2026-2776 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-2776?

CVE-2026-2776 has a CVSS score of 10.0 (CRITICAL) and an EPSS exploitation probability of 0.05%.

HOME VULNERABILITIESCVE-2026-2776

CRITICAL

CVE-2026-2776

Published: February 24, 2026· Updated: Feb 28, 2026

10.0

CVSS v3.1

EPSS:0.05%probability of exploitation in 30 daysPercentile:16.8th

Official Description

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

NVD Source

Technical Analysis

CVE-2026-2776 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 10.0.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges Req.None

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Affected Vendors & Products

Mozilla2 products

firefoxthunderbird

Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Exploit-DB

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

PacketStorm

Security advisories & exploits

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2026-13/

ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2026-14/

ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2026-15/

ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2026-16/

ADVISORYhttps://www.mozilla.org/security/advisories/mfsa2026-17/

News & Research Mentioning CVE-2026-2776

SWITCH EV swtchenergy.com

CISA Alerts· Feb 26, 2026

View CSAF Summary Successful exploitation of these vulnerabilities could allow attackers to impersonate charging stations, hijack sessions, suppress or misroute legitimate traffic to cause large-scale denial of service, and manipulate data sent to the backend. The following versions of SWITCH EV swtchenergy.com are affected: swtchenergy.com vers:all/* (CVE-2026-27767, CVE-2026-25113, CVE-2026-25778, CVE-2026-27773) CVSS Vendor Equipment Vulnerabilities v3 9.4 SWITCH EV SWITCH EV swtchenergy.com Missing Authentication for Critical Function, Improper Restriction of Excessive Authentication Attempts, Insufficient Session Expiration, Insufficiently Protected Credentials Background Critical Infrastructure Sectors: Energy, Transportation Systems Countries/ [xlite_meta score:63 src:CISA Alerts xlite_fp:d18277bbdde0772a8f2eec37bc286212b473ab2c6da3a1e7dd3b7d5e6b1d96ec]