CVE•Published 2026-02-24•Modified 2026-06-30•1 article on news•6 live references•NVD data

CVE-2026-2777Mozilla · Firefox

Vulnerability data via NVD (ingested)

CVSS v3.1

9.8

CRITICAL

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

EPSS percentile

—

Weaknesses (CWE)

CWE-269Improper Privilege Management

Description

Privilege escalation in the Messaging System component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Timeline

Published 2026-02-24

Modified 2026-06-30

External references

NVD MITRE Exploit-DB GitHub PoC Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-2777

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Mozilla Firefox"

All exposed Mozilla Firefox instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Firefox"

HTTP body or banner mentions "Firefox" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-2777