Description

Privilege escalation due to weak configuration while temporary file handling.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-22T10:17:09.243Z",
  "pubdate": "2026-09-22T10:17:09.243Z",
  "executiveSummary": "This vulnerability pertains to improper temporary file handling, which introduces a severe privilege escalation risk. The flaw resides in the weak configuration of how the application generates, manages, or handles temporary files, typically within shared or predictable system directories.\nThe vulnerability allows an unprivileged local attacker to manipulate these temporary files—often through race conditions, symlink attacks, or unauthorized read/write access—to escalate their privileges to that of the user running the vulnerable service or process, which is frequently root or SYSTEM.\nThe primary risk implication is a total compromise of the affected system's integrity and confidentiality. An attacker must generally have local access to the target host to exploit this condition, but no prior high-level privileges are required. This represents a significant security oversight in the implementation of temporary storage, effectively subverting file system access controls and environment security models.\nRemediation requires auditing file handling routines to ensure the use of secure APIs that enforce atomic file creation, restricted permissions (e.g., restricted umasks or exclusive creation flags), and the utilization of secure, process-specific directories.",
  "technicalDetails": "The root cause of this vulnerability is the failure to employ secure, collision-resistant, and permission-restricted mechanisms when creating temporary files. When an application creates temporary files in publicly accessible directories (such as /tmp or C:\\Windows\\Temp), it often relies on predictable naming conventions or fails to set appropriate file system permissions, such as restrictive ACLs or mode bits.\nThe exploitation flow typically follows a Time-of-Check Time-of-Use (TOCTOU) pattern or a symlink attack. If an application performs insecure operations like 'check if file exists, then create/write', a local attacker can exploit this window. By pre-creating a symbolic link at the predicted temporary file path, an attacker can direct the application to write data into a sensitive system file (e.g., /etc/passwd or system configuration files), effectively leading to arbitrary file overwrite, file disclosure, or code execution.\nIf the application runs with elevated privileges, the attacker leverages this to perform an action on behalf of the elevated process. For instance, if the application writes diagnostic logs or temporary configuration caches without verifying the file owner or ensuring that the file is not a symbolic link, the attacker can manipulate the file descriptor to point to a target owned by the root user.\nWhen the vulnerable component processes the temporary file, it operates under the authority of the elevated process, inadvertently modifying or exposing files outside the intended scope. This allows for the injection of malicious content, such as adding a new user with UID 0 to the password file or overwriting binaries that are executed by privileged services. The payload behavior is contingent on the specific function that processes the file; however, the post-exploitation impact almost universally results in vertical privilege escalation.\nThis vulnerability is highly dependent on the local operating environment. It does not require network exposure, as the attack is strictly local-based. Authentication is not required, as the attacker merely needs a shell or local terminal access to perform the file system manipulation. Successful exploitation grants the attacker the execution context of the target application, which, if run as a service, effectively provides control over the host."
}