DOM Content Process Privilege Escalation in Firefox

Privilege escalation in the DOM: Content Processes component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

Casky was already ahead

This CVE exploits attack patterns that Casky's 224matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

CVE-2026-16379 is a critical privilege escalation vulnerability (CVSS 9.8) in Firefox and Thunderbird's DOM content processes that allows attackers to elevate their privileges within the browser sandbox. This vulnerability affects the fundamental isolation mechanisms that protect users from malicious web content, impacting millions of users running vulnerable versions of Firefox (pre-153), Firefox ESR (pre-140.13), Thunderbird (pre-153), and Thunderbird ESR (pre-140.13). The flaw stems from improper access control (CWE-269) in how the DOM processes handle privilege boundaries, creating a direct pathway for attackers to break out of content process restrictions and gain elevated system access.

Casky's 224 mapped security skills leverage Claude AI with extended reasoning to detect the attack patterns associated with TA0004 (Privilege Escalation) techniques by analyzing behavioral indicators across multiple dimensions. Practitioners using Casky would identify suspicious patterns including: abnormal inter-process communication between content processes and parent processes, unexpected system calls attempting to access kernel-level resources from sandboxed contexts, DOM manipulation sequences that probe privilege boundaries, and memory corruption signatures targeting process isolation structures. The platform's skills would flag exploitation attempts through detection of rapid successive privilege boundary checks, unusual capability requests, and process spawning behavior inconsistent with normal browser operation—allowing security teams to catch this attack pattern before full privilege elevation occurs.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

224 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-16379.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

penetration testing · medium

Run

MITRE ATT&CK Techniques

TA0004

Investigate the attack patterns behind CVE-2026-16379

Casky has 224 skills that investigate the attack patterns behind CVE-2026-16379. Run one and get CVSS-scored findings in 3 minutes.

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