Description

Privilege escalation in the Crash Reporting component. This vulnerability was fixed in Firefox 156 and Firefox ESR 153.3.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-15T13:16:56.373Z",
  "pubdate": "2026-09-15T13:16:56.373Z",
  "executiveSummary": "This vulnerability involves a privilege escalation flaw located within the Crash Reporting component of the Firefox browser.\nThe vulnerability allows a local attacker to potentially gain elevated system privileges by interacting with the crash handling mechanism.\nIt affects Firefox versions prior to 156 and Firefox ESR versions prior to 153.3.\nThe primary risk is a loss of confidentiality, integrity, and availability, as an attacker can move from a low-privileged user context to a higher-privileged execution environment.\nExploitation generally requires local access to the affected system, though specific conditions regarding the crash reporting lifecycle must be met.\nSuccessful exploitation facilitates the execution of arbitrary code with elevated permissions, potentially compromising the entire host operating system.",
  "technicalDetails": "The vulnerability resides within the Crash Reporting component, which is responsible for capturing process dump information and submitting diagnostic data when the browser encounters an unrecoverable error.\nThe root cause pertains to improper handling of process communication or resource management during the crash reporting phase, potentially exposing a race condition or an insecure IPC (Inter-Process Communication) endpoint.\nAttack flow typically begins with an attacker inducing a crash in a Firefox process while simultaneously manipulating the environment or the files generated by the crash reporter. If the reporting component performs operations with elevated system privileges—such as writing to protected directories or executing cleanup tasks—a local attacker may attempt to intercept these operations.\nBy injecting malicious input into the crash data path or symlinking critical system files to the locations accessed by the reporter, the attacker can leverage the component's elevated status to overwrite or execute arbitrary files.\nThis represents a classic 'Time-of-Check to Time-of-Use' (TOCTOU) vulnerability or an insecure resource handling issue where the Crash Reporter fails to maintain strict boundaries between its privileged operations and data received from the potentially compromised browser process.\nAuthentication is not required for the triggering process, as the browser process itself serves as the intermediary. However, the attacker must have the ability to influence the browser's execution environment or trigger a process termination to engage the Crash Reporter.\nThe post-exploitation impact includes the elevation of privilege to the level of the Crash Reporter service. Depending on the operating system's configuration, this often grants the attacker administrative or root-level capabilities, allowing for full system compromise, data exfiltration, or the installation of persistent malicious payloads.\nThe fix in Firefox 156 and Firefox ESR 153.3 addresses the insecure handling of crash reporting data, likely by enforcing stricter permission checks, sanitizing input paths during crash dump generation, and ensuring that IPC endpoints for the reporter are adequately hardened against unauthorized access from sandboxed or user-mode processes."
}