CVE-2026-8964
📛 CVE Title
Spoofing issue in the Popup Blocker component
Description
Spoofing issue in the Popup Blocker component. 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 12:30 UTC
- Last updated
- 2026-05-19 17:10 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/8xxx/CVE-2026-8964.json
- Linked Threat
- CVE-2026-8964 — CVE-2026-8964
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 14:57:04 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
- 7.33% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24
NVD-assigned CWE(s):
CWE-451
(differs from the CNA list above)
NVD / KEV / EPSS data refreshed 2026-05-25 00:32 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
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-2026-30915 - Assigner
- mozilla
- Published
- May 19, 2026, 12:30:08 PM
- Updated
- May 19, 2026, 5:10:54 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
- 0.0300
- Aliases
-
GHSA-x37c-vm4v-4wvx
ENISA description: Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
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-2026-8964 rapid7:attackerkb.com
- http://cwe.mitre.org/data/definitions/451.html rapid7:cwe.mitre.org
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-30915 rapid7:euvd.enisa.europa.eu
- https://www.mozilla.org/security/advisories/mfsa2026-50/ tenable:www.mozilla.org
- https://nvd.nist.gov/vuln/detail/CVE-2026-8964 tenable:nvd.nist.gov
- https://www.cve.org/CVERecord?id=CVE-2026-8964 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=2025170 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=2025170 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 (18)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:app.opencve.io
Remediation No vendor fix or workaround currently provided. OpenCVE Recommended Actions Upgrade Firefox to version 151 or newer Configure the popup blocker to strict mode and disable any exception lists for unknown sites Educate users to recognize and avoid deceptive pop‑ups Generated by OpenCVE AI on May 19, 2026 at 19:25 UTC.
2026-05-23 22:18 UTC -
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 .
2026-05-23 22:18 UTC -
web:cybersecuritynews.com
Microsoft has released its April 2026 Patch Tuesday security update, addressing 168 vulnerabilities across its product portfolio including one actively exploited zero-day and one publicly disclosed flaw that organizations must prioritize immediately.
2026-05-23 22:18 UTC -
web:guide.sonatype.com
Technical security analysis for CVE-2026-8964 . CVSS 7.5 severity. View CVSS vectors, CWE classifications, and exploit maturity ratings.
2026-05-23 22:18 UTC -
web:nvd.nist.gov
An official website of the United States government Here's how you know
2026-05-23 22:18 UTC -
web:portal.msrc.microsoft.com
The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.
2026-05-23 22:18 UTC -
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 ...
2026-05-23 22:18 UTC -
web:www.msn.com
Original story: Microsoft has released an emergency patch for a vulnerability in the company's Office programs that's already being exploited by hackers.
2026-05-23 22:18 UTC -
web:www.thehackerwire.com
How do I fix or mitigate CVE-2026-8964 ? To protect against CVE-2026-8964 , you should: (1) Apply the latest security patches from the vendor, (2) Check official security advisories for specific remediation steps, (3) Update affected software to the latest version, and (4) Monitor your systems for any signs of exploitation.
2026-05-23 22:18 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-05-23 22:18 UTC -
web:attack.mitre.org
This mitigation can be implemented through the following measures: Regular Operating System Updates Implementation: Apply the latest Windows security updates monthly using WSUS (Windows Server Update Services) or a similar patch management solution. Configure systems to check for updates automatically and schedule reboots during maintenance ...
2026-05-26 02:58 UTC -
web:blog.talosintelligence.com
Microsoft has released its monthly security update for May 2026 , which includes 137 vulnerabilities affecting a range of products, including 16 that Microsoft marked as "critical".
2026-05-26 02:58 UTC -
web:securitricks.com
CVE CVE-2026-8964 - Score : 7.5 - Source : security@mozilla.org - Description : Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
2026-05-26 02:58 UTC -
web:techcommunity.microsoft.com
We wanted to tell you how to address the Exchange Server May 2026 vulnerability CVE - 2026 -42897.
2026-05-26 02:58 UTC -
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.
2026-05-26 02:58 UTC -
web:www.crowdstrike.com
Microsoft has released security updates for 130 vulnerabilities, including 30 critical, in its May 2026 Patch Tuesday rollout.
2026-05-26 02:58 UTC -
web:www.forbes.com
Updated May 17: This article, originally published May 16, has been updated to include further details on the emergency mitigation process recommended after the CVE - 2026 -42897 Microsoft Exchange ...
2026-05-26 02:58 UTC -
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.
2026-05-26 02:58 UTC
AI Forensic Analysis
Only Available for Registered Users. Sign in to view.
Raw JSON
The full cvelistV5 record. Download as CVE-2026-8964.json.
{
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"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",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-8964",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-19T15:00:04.518591Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-451",
"description": "CWE-451 User Interface (UI) Misrepresentation of Critical Information",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-05-19T15:00:48.758Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "Firefox",
"vendor": "Mozilla",
"versions": [
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "151",
"versionType": "rpm"
}
]
},
{
"product": "Thunderbird",
"vendor": "Mozilla",
"versions": [
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "151",
"versionType": "rpm"
}
]
}
],
"credits": [
{
"lang": "en",
"value": "Satoki Tsuji"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thunderbird 151."
}
],
"value": "Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thunderbird 151."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-19T17:10:54.077Z",
"orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
"shortName": "mozilla"
},
"references": [
{
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2025170"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-46/"
},
{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-50/"
}
],
"title": "Spoofing issue in the Popup Blocker component"
}
},
"cveMetadata": {
"assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
"assignerShortName": "mozilla",
"cveId": "CVE-2026-8964",
"datePublished": "2026-05-19T12:30:08.140Z",
"dateReserved": "2026-05-19T12:30:07.287Z",
"dateUpdated": "2026-05-19T17:10:54.077Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}