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Mozilla Firefox CVE-2026-8966

| EUVDEUVD-2026-30918 HIGH
Information Exposure (CWE-200)
2026-05-19 mozilla GHSA-wq4p-4w8c-6qcg
Information Disclosure Mozilla Suse Red Hat
High
Disputed · 7.5 NVD
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Severity by source

Sources disagree (Low–High)
NVD PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
SUSE
HIGH
qualitative
Red Hat
3.4 LOW
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 VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

3
Analysis Generated
May 20, 2026 - 17:26 vuln.today
CVSS changed
May 20, 2026 - 17:22 NVD
7.5 (HIGH)
CVE Published
May 19, 2026 - 12:30 nvd
UNKNOWN (no severity yet)

DescriptionCVE.org

Information disclosure in the IP Protection component. This vulnerability was fixed in Firefox 151.

AnalysisAI

Information disclosure in Mozilla Firefox versions prior to 151 affects the IP Protection component, allowing remote unauthenticated attackers to obtain sensitive information over the network without user interaction. The flaw carries a CVSS score of 7.5 driven entirely by confidentiality impact (C:H/I:N/A:N), and while no public exploit is identified at time of analysis, the very low EPSS score of 0.02% (4th percentile) suggests minimal active exploitation interest. Mozilla addressed the issue in Firefox 151 via security advisories MFSA2026-46 and MFSA2026-50.

Technical ContextAI

The flaw resides within Firefox's IP Protection component, a privacy-oriented feature designed to mask or proxy the user's originating IP address from web destinations (similar in concept to Apple Private Relay). The CWE-200 classification (Exposure of Sensitive Information to an Unauthorized Actor) indicates the root cause is improper restriction or leakage of data that should have been protected by the IP Protection layer - meaning the very subsystem intended to shield user network identity was itself leaking information. The CPE string cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* identifies Mozilla Firefox as the affected application across versions prior to the fix.

RemediationAI

Vendor-released patch: Firefox 151 - upgrade all Firefox installations to version 151 or later, per Mozilla advisories MFSA2026-46 (https://www.mozilla.org/security/advisories/mfsa2026-46/) and MFSA2026-50 (https://www.mozilla.org/security/advisories/mfsa2026-50/). For environments unable to update immediately, a targeted compensating control is to disable the IP Protection feature via about:config or enterprise policy (network.vpn.* / privacy.ipProtection settings depending on build), which eliminates the vulnerable code path at the cost of losing the privacy benefit the feature provides. Organizations using managed Firefox deployments should push the updated MSI/PKG/DEB through their existing software distribution tooling, and verify version compliance via about:support telemetry.

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Same weakness CWE-200 – Information Exposure

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CVE-2016-6415 HIGH POC
7.5
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6.5
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9.8
CVE-2017-16894 HIGH POC
7.5
CVE-2017-11165 CRITICAL POC
9.8
CVE-2016-2388 MEDIUM POC
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CVE-2016-1561 HIGH POC
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Same technique Information Disclosure

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CVE-2013-2251 CRITICAL POC
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CVE-2025-24813 CRITICAL POC
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CVE-2015-1701 HIGH POC
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CVE-2017-0147 HIGH POC
7.5
CVE-2014-6324 HIGH POC
8.8
CVE-2023-7028 CRITICAL POC
10.0
CVE-2017-0213 HIGH POC
7.3

Vendor StatusVendor

SUSE

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

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CVE-2026-8966 vulnerability details – vuln.today
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