Privilege escalation via unauthorized parent TCP sockets
Published Apr 21, 2026 · Updated Apr 21, 2026
Privilege escalation in Firefox and Thunderbird before 150 or ESR 140.10 allows remote attackers to gain parent-process access via attacker-controlled content. Networking IPC handlers create parent TCP client and server sockets for child-process requests without checking the controlling preference or sender authorization. Exploitation requires user interaction and prior code execution in a content process, after which loopback and local-network services become reachable through the privileged parent process.
Summary
What happened
Privilege escalation in Firefox and Thunderbird before 150 or ESR 140.10 allows remote attackers to gain parent-process access via attacker-controlled content. Networking IPC handlers create parent TCP client and server sockets for child-process requests without checking the controlling preference or sender authorization. Exploitation requires user interaction and prior code execution in a content process, after which loopback and local-network services become reachable through the privileged parent process.
The record
- CVE
- CVE-2026-6761
- Published
- Apr 21, 2026
- Updated
- Apr 21, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-269, T1068
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 21, 2026CVE publishedPublication date reported by the CVE source.
- Apr 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Child-to-parent TCP socket authorization reproductionproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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