CVE-2026-15719 Overview
CVE-2026-15719 affects Mozilla Firefox versions prior to 152.0.6. Mozilla acknowledged that exploit code for this flaw is publicly available, though no in-the-wild attacks have been observed. The vulnerability requires user interaction and can be triggered over the network, resulting in limited impact to confidentiality and integrity.
Mozilla addressed the issue in Firefox 152.0.6 and documented it in security advisory MFSA-2026-67. The associated bug tracker entry is Mozilla Bug #2043820.
Critical Impact
Public exploit code exists for this browser vulnerability. Attackers can leverage crafted web content to compromise confidentiality and integrity of user data when a victim visits a malicious page.
Affected Products
- Mozilla Firefox versions prior to 152.0.6
- Deployments matching CPE cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
- Enterprise environments running unpatched Firefox on Windows, macOS, and Linux
Discovery Timeline
- 2026-07-14 - CVE CVE-2026-15719 published to NVD
- 2026-07-14 - Last updated in NVD database
Technical Details for CVE-2026-15719
Vulnerability Analysis
CVE-2026-15719 is a browser-side vulnerability in Mozilla Firefox fixed in release 152.0.6. The advisory does not enumerate a specific CWE category, and NVD lists the weakness as NVD-CWE-noinfo. Mozilla has explicitly stated that working exploit code is public, elevating operational risk despite the moderate scoring.
Exploitation requires the victim to interact with attacker-controlled content, such as loading a crafted web page. Successful exploitation yields limited disclosure and modification capabilities within the browser context. No privileges are required on the target, and the attack scope remains unchanged.
The combination of a network attack vector and low complexity means widespread targeting is feasible once attackers weaponize the public proof of concept. Availability is not affected, suggesting the flaw does not crash the browser process reliably.
Root Cause
Mozilla has not published the underlying weakness class in the public advisory, and NVD carries the placeholder NVD-CWE-noinfo. Technical details reside in the restricted Mozilla Bug Report #2043820, which is typically gated until broader patch adoption occurs.
Attack Vector
The attack originates over the network and requires user interaction. A victim must navigate to attacker-controlled web content or open a crafted resource in a vulnerable Firefox build. Refer to MFSA-2026-67 for Mozilla's guidance on the exploitation path.
No synthesized proof-of-concept code is reproduced here. The publicly available exploit referenced by Mozilla should be reviewed only within controlled research environments.
Detection Methods for CVE-2026-15719
Indicators of Compromise
- Firefox client versions below 152.0.6 reporting through asset inventory or user-agent telemetry
- Unusual child process activity spawned from firefox.exe or firefox following browsing sessions to untrusted domains
- Outbound connections from Firefox to newly registered or low-reputation domains coinciding with user navigation events
Detection Strategies
- Inventory Firefox installations across managed endpoints and flag any build prior to 152.0.6 for remediation
- Monitor browser telemetry for anomalous script execution, unexpected file writes, or credential-store access after visits to untrusted origins
- Correlate web proxy logs with endpoint process lineage to identify users interacting with pages hosting the public exploit
Monitoring Recommendations
- Alert on Firefox versions that fail to auto-update within the enterprise patch window
- Track threat intelligence feeds and vendor updates referencing the public exploit for CVE-2026-15719
- Baseline normal Firefox network egress and flag deviations tied to crafted content delivery
How to Mitigate CVE-2026-15719
Immediate Actions Required
- Upgrade all Firefox installations to version 152.0.6 or later without delay
- Enforce browser auto-update policies through enterprise configuration management
- Communicate with users to restart Firefox after updates apply, ensuring the patched binary loads
Patch Information
Mozilla released the fix in Firefox 152.0.6. Full remediation details are available in Mozilla Security Advisory MFSA-2026-67. Administrators should validate patch deployment through version reporting rather than relying solely on update notifications.
Workarounds
- Restrict Firefox usage on high-value systems until patching completes
- Deploy web filtering to block untrusted or unclassified destinations that could host the public exploit
- Disable or restrict browser features that increase attack surface where policy permits, then re-enable after patching
# Verify installed Firefox version on Linux endpoints
firefox --version
# Windows PowerShell version check
Get-ItemProperty "HKLM:\SOFTWARE\Mozilla\Mozilla Firefox" | Select-Object CurrentVersion
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
