CVE-2026-6762
Published: 21 April 2026
Description
Spoofing issue in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Reveals spoofed logon attempts through unexpected previous logon timestamps upon legitimate login.
Training specifically addresses recognizing spoofed communications and phishing that enable authentication bypass.
Requiring verifiable identity evidence at appropriate assurance levels makes it substantially harder for attackers to successfully spoof or impersonate users to obtain accounts.
Unique device authentication makes successful spoofing of device identity substantially more difficult to achieve.
Unique identification of non-organizational users reduces the feasibility of authentication bypass by spoofing.
Unique identification and authentication of services before communications makes spoofing of service identities substantially harder.
Isolated trusted path ensures the user interacts only with genuine system components, preventing spoofing of authentication interfaces or prompts.
Directly counters DNS response spoofing by requiring cryptographic origin authentication artifacts from the authoritative source.
Security SummaryAI
CVE-2026-6762 is a spoofing vulnerability (CWE-290) in the DOM: Core & HTML component of Mozilla Firefox and Thunderbird. It affects versions of these products prior to Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. The issue was published on 2026-04-21 and carries a CVSS v3.1 base score of 6.3 (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L).
Attackers can exploit this vulnerability remotely over the network with low complexity and no required privileges, though it demands user interaction such as clicking a malicious link or engaging with crafted content. Successful exploitation enables limited impacts on confidentiality, integrity, and availability within the unchanged scope, potentially allowing spoofed elements in the DOM to mislead users.
Mozilla's security advisories (MFSA2026-30, MFSA2026-31, MFSA2026-32, and MFSA2026-33) and Bugzilla entry 2021080 detail the fix applied in the listed versions. Mitigation requires updating affected Firefox and Thunderbird installations to these patched releases.
Details
- CWE(s)
Affected Products
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
DOM spoofing enables deception via malicious links or crafted web content, directly facilitating spearphishing links, user execution through malicious links, and drive-by compromise scenarios.