CVE-2026-8964

Name: CVE-2026-8964
Creator: NVD / NIST
Published: 2026-05-19T14:16:52.823+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.30%

Last modified Jun 17, 2026

CVE-2026-8964 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.. EPSS estimates a 0.30% chance of exploitation in the next 30 days.

Description

Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

Metrics

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

EPSS Probability

0.30%

21.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-451

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 151.0.0
Mozilla	Thunderbird	< 151.0.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2025170Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-46/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-50/Vendor Advisory

Timeline

Published: May 19, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-8964?

Spoofing issue in the Popup Blocker component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

How severe is CVE-2026-8964?

CVE-2026-8964 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.

How do I fix CVE-2026-8964?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-8964?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST