Sandbox escape via unchecked capture-file IPC paths
Published Apr 21, 2026 · Updated Jul 15, 2026
Sandbox escape in Mozilla Firefox before 150 allows attackers to write capture files via unchecked WebRender IPC paths. WebRenderBridgeParent::RecvStartCaptureSequence forwards an attacker-controlled destination to capture-file writes without validation; Thunderbird shares the affected component. Exploitation requires a compromised content process and writes with parent-process privileges, rather than inherently granting root access.
Summary
What happened
Sandbox escape in Mozilla Firefox before 150 allows attackers to write capture files via unchecked WebRender IPC paths. WebRenderBridgeParent::RecvStartCaptureSequence forwards an attacker-controlled destination to capture-file writes without validation; Thunderbird shares the affected component. Exploitation requires a compromised content process and writes with parent-process privileges, rather than inherently granting root access.
The record
- CVE
- CVE-2026-6750
- Published
- Apr 21, 2026
- Updated
- Jul 15, 2026
- Vendor
- libuser Project
- Product
- Red Hat Enterprise Linux 9
- Classifications
- CWE-266, CWE-269, T1068
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 21, 2026CVE publishedPublication date reported by the CVE source.
- Jul 15, 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?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- recv_start_capture_sequence_poc.jsproof of concept · unverified
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Technologies
Your stack
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Your stack
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