CVE-2026-8960

Description

Spoofing issue in WebExtensions. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

Overview

State: PUBLISHED
Assigner (CNA): mozilla
CVSS severity: high
CVSS score: 7.5 / 10
CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Effective score: 7.5 / 10 HIGH source: CNA overview
CWE(s): —
Reserved: 2026-05-19
Published: 2026-05-19 12:29 UTC
Last updated: 2026-05-19 17:10 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/8xxx/CVE-2026-8960.json
Linked Threat: CVE-2026-8960 — CVE-2026-8960

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-19 14:16:52 UTC
NVD last modified: 2026-05-20 14:20:06 UTC
NVD CVSS v3.1: 7.5 / 10 HIGH source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Exploitability subscore: 3.9 / 10
Impact subscore: 3.6 / 10
EPSS score: 0.0003 (probability of exploitation in next 30 days)
EPSS percentile: 8.31% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

NVD-assigned CWE(s): CWE-290 (differs from the CNA list above)

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-30909
Assigner: mozilla
Published: May 19, 2026, 12:29:57 PM
Updated: May 19, 2026, 5:10:53 PM
EUVD base score (CVSS 3.1): 7.5 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EUVD-reported EPSS: 0.0400
Aliases: GHSA-57v8-q85x-pwx6

ENISA description: Spoofing issue in WebExtensions. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

EUVD references (3)

Affected products (2)

Vendor	Product	Versions	Platforms
Mozilla	Firefox	`151` (unaffected)	—
Mozilla	Thunderbird	`151` (unaffected)	—

Affected products — CPE 2.3 (2) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

Web references (11)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

http://www.mozilla.org/security/announce/2026/mfsa2026-50.html rapid7:www.mozilla.org
http://www.mozilla.org/security/announce/2026/mfsa2026-46.html rapid7:www.mozilla.org
https://attackerkb.com/topics/CVE-2026-8960 rapid7:attackerkb.com
http://cwe.mitre.org/data/definitions/290.html rapid7:cwe.mitre.org
https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-30909 rapid7:euvd.enisa.europa.eu
https://www.mozilla.org/security/advisories/mfsa2026-50/ tenable:www.mozilla.org
https://nvd.nist.gov/vuln/detail/CVE-2026-8960 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-8960 tenable:www.cve.org
https://www.first.org/epss/ tenable:www.first.org
https://www.mozilla.org/security/advisories/mfsa2026-46/ tenable:www.mozilla.org
https://bugzilla.mozilla.org/show_bug.cgi?id=1940116 tenable:bugzilla.mozilla.org

NVD-tagged references (3)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://bugzilla.mozilla.org/show_bug.cgi?id=1940116 security@mozilla.org Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-46/ security@mozilla.org Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-50/ security@mozilla.org Vendor Advisory

Remediations (15)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2026-8960 - Vulnerability Details - OpenCVE

web:app.opencve.io

Based on the CVE description, the vulnerability is a spoofing issue in Firefox WebExtensions. The impact of allowing malicious extensions or scripts to impersonate legitimate sites or extensions is inferred from the term "spoofing". This can compromise user confidentiality and trust by presenting deceptive content as genuine.

2026-05-23 22:18 UTC
CVE-2026-8960 - Spoofing issue in WebExtensions

web:cvefeed.io

The following products are affected by CVE-2026-8960 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

2026-05-23 22:18 UTC
CVE-2026-8960 | Security Details | Sonatype Guide

web:guide.sonatype.com

Technical security analysis for CVE-2026-8960 . CVSS 2.1 severity. View CVSS vectors, CWE classifications, and exploit maturity ratings.

2026-05-23 22:18 UTC
Nvd - Cve-2026-42960

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-05-23 22:18 UTC
May 12, 2026—Hotpatch KB5089466 (OS Builds 26200.8390 and 26100.8390 ...

web:support.microsoft.com

This Hotpatch update for Windows 11, version 25H2 and 24H2 (KB5089466) includes security improvements. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates. To ...

2026-05-23 22:18 UTC
CVE-2026-8960 | Ubuntu

web:ubuntu.com

Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things.

2026-05-23 22:18 UTC
KB5086096: .NET 8.0 Security Patch - Windows/Linux/macOS (2026)

web:www.anavem.com

KB5086096 is a security update that addresses multiple vulnerabilities in .NET 8.0 runtime and SDK components, including CVE - 2026 -0145 and CVE - 2026 -0146, affecting cross-platform deployments on Windows, Linux, and macOS.

2026-05-23 22:18 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-05-23 22:18 UTC
Rapid7 Vulnerability Database

web:www.rapid7.com

Rapid7's VulnDB is curated repository of vetted computer software exploits and exploitable vulnerabilities.

2026-05-23 22:18 UTC
CVE-2026-8960 - High Vulnerability - TheHackerWire

web:www.thehackerwire.com

CVE-2026-8960 is a High severity vulnerability (CVSS 7.5). Spoofing issue in WebExtensions. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

2026-05-23 22:18 UTC
CISA Warns of Exploited Microsoft Defender 0-Day Flaws

web:cyberpress.org

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .

2026-05-26 02:58 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-05-26 02:58 UTC
Critical Patches Issued for Microsoft Products, May 12, 2026

web:www.cisecurity.org

<p>Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for remote code execution. Successful exploitation of the most severe of these vulnerabilities could result in an attacker gaining the same privileges as the logged-on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or ...

2026-05-26 02:58 UTC
Rapid7 Vulnerability Database

web:www.rapid7.com

vulnerability MFSA2026-46 Firefox: Security Vulnerabilities fixed in Firefox 151 ( CVE-2026-8960 )

2026-05-26 02:58 UTC
Patch Tuesday May 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-05-26 02:58 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-8960.json.

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              "baseScore": 7.5,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
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    "dateReserved": "2026-05-19T12:29:56.291Z",
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