CVE-2014-1511: Mozilla Firefox popup blocker bypass via unspecified vectors

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 18 September 2026. Confidence: medium.

high priorityCVSS 3.1 is 9.8 critical and EPSS is very high, but the flaw is a popup blocker bypass with no documented KEV listing or described code execution, so it is rated high rather than critical.

What it is

Mozilla Firefox before 28.0, Firefox ESR 24.x before 24.4, Thunderbird before 24.4, and SeaMonkey before 2.25 allow remote attackers to bypass the popup blocker. The flaw is an improper privilege management issue (CWE-269) that undermines a browser security control meant to prevent unsolicited windows. Because the bypass is network-reachable with no authentication or user interaction per the CVSS vector, it matters as a defense-evasion primitive that can be chained with other attacks.

Impact

An attacker can force popup windows that the browser would normally block, enabling unwanted content delivery, phishing, or drive-by behavior. The record does not describe further privilege gain beyond the bypass itself.

Attack surface

Reached over the network via crafted web content or messages rendered by the affected Mozilla products. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N) indicates no authentication and no user interaction are required, though the description does not detail the exact trigger.

Exploitation

Not listed in CISA KEV and no ransomware associations are documented. EPSS is high (0.83633, 99.672 percentile), and one reference (Mozilla Bugzilla bug 982909) is tagged Exploit, indicating public exploit-related material exists.

What to do

• Upgrade Firefox to 28.0 or later, Firefox ESR to 24.4 or later, Thunderbird to 24.4 or later, and SeaMonkey to 2.25 or later.
• Apply the vendor and distribution advisories (Mozilla MFSA 2014-29, Red Hat RHSA-2014-0310/0316, Debian DSA-2881/2911, Ubuntu USN-2151-1, openSUSE and SUSE advisories) for managed packages.
• If immediate upgrade is not possible, restrict browsing to trusted sites and consider disabling or tightly controlling JavaScript and popup-related content in the affected clients.
• Track end-of-life Mozilla clients and remove or isolate unsupported versions from user endpoints.

Detection

• Monitor for unexpected or excessive popup window creation from browser processes, especially from untrusted origins.
• Alert on use of known-vulnerable Firefox, Thunderbird, or SeaMonkey versions via endpoint software inventory.
• Review proxy and DNS logs for known malicious or phishing domains that may rely on popup delivery.
• Correlate browser crash or anomaly telemetry with popup-related events around the time of suspicious browsing.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.