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Mozilla Firefox EUVDEUVD-2026-46232

| CVE-2026-16394 CRITICAL
Protection Mechanism Failure (CWE-693)
2026-07-21 mozilla GHSA-qvxh-vvjm-vpwg
Authentication Bypass Red Hat Mozilla Suse
Critical
Disputed · 9.1 Vendor: mozilla
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Severity by source

Sources disagree (Medium–Critical)
Vendor (mozilla) PRIMARY
9.1 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
vuln.today AI
8.1 HIGH

Network-delivered web content with no auth (AV:N/PR:N), but a client-side browser bug realistically needs the victim to load a page, so UI:R; high C/I, no availability impact.

3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
SUSE
CRITICAL
qualitative
Red Hat
6.1 MEDIUM
qualitative

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorVendor: mozilla

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

Lifecycle Timeline

4
Analysis Generated
Jul 21, 2026 - 20:23 vuln.today
CVSS changed
Jul 21, 2026 - 20:22 NVD
9.1 (CRITICAL)
CVE Published
Jul 21, 2026 - 12:38 cve.org
UNKNOWN (no severity yet)
CVE Published
Jul 21, 2026 - 12:38 cve.org
CRITICAL 9.1

DescriptionCVE.org

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 153.

Articles & Coverage 1

News Critical DOM Security Bypass in Mozilla Firefox - CVE-2026-16394 Jul 21, 2026

AnalysisAI

Protection mechanism failure in the DOM: Security component of Mozilla Firefox lets remote attackers bypass a browser security mitigation, undermining defenses that isolate web content and enforce origin/policy boundaries. Mozilla rates this Critical (CVSS 9.1) with high confidentiality and integrity impact and no authentication or user interaction required per the assigned vector; it is corrected in Firefox 153 (MFSA 2026-68). There is no public exploit identified at time of analysis and it is not listed in CISA KEV.

Technical ContextAI

The flaw lives in Firefox's DOM: Security subsystem - the layer that enforces web security invariants such as the same-origin policy, Content Security Policy, sandboxing, and other exploit-mitigation controls that constrain what scripted web content may do. The CWE-693 (Protection Mechanism Failure) classification indicates the vulnerability is not a memory-corruption bug but a defeat of an existing safeguard: attacker-controlled web content can circumvent a control that was designed to block it. The affected CPE is cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* (all pre-153 versions), and Mozilla-internal tagging labels it an Authentication/Authorization-style bypass, consistent with a policy-enforcement boundary being evaded rather than code execution being achieved directly.

RemediationAI

Vendor-released patch: Firefox 153 - upgrade all Firefox installations to 153 or later, which is the primary and complete fix per MFSA 2026-68 (https://www.mozilla.org/security/advisories/mfsa2026-68/). In managed environments, push the update through your software distribution/auto-update channel and confirm the built-in updater is enabled so endpoints converge quickly. If ESR is in use, hold for and apply the corresponding ESR release once Mozilla confirms it (not established in the current data). Because this is a mitigation bypass with no documented standalone exploit, no reliable feature-level workaround is published; as an interim compensating control you can restrict browsing to trusted sites via enterprise policy or a web proxy/URL filter to reduce exposure to attacker-controlled pages, accepting the usability trade-off, but this is not a substitute for the upgrade.

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Same weakness CWE-693 – Protection Mechanism Failure

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Same technique Authentication Bypass

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Vendor StatusVendor

SUSE

Severity: Critical
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Performance Computing 15 SP7 Affected
SUSE Linux Enterprise Module for Desktop Applications 15 SP7 Affected
SUSE Linux Enterprise Module for Package Hub 15 SP7 Affected

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EUVD-2026-46232 vulnerability details – vuln.today
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