CVE-2026-25265: Privilege Escalation via File Handling

CVE-2026-25265 Overview

CVE-2026-25265 is a local privilege escalation vulnerability caused by weak configuration during temporary file handling. The flaw is tracked under CWE-378: Creation of Temporary File With Insecure Permissions and was disclosed in the Qualcomm June 2026 Security Bulletin. A local attacker with low privileges can leverage insecure temporary file permissions to escalate to higher privileges, compromising confidentiality, integrity, and availability across the affected component. The scope is marked as changed, meaning the vulnerable component can affect resources beyond its own security authority.

Critical Impact
A local, low-privileged attacker can escalate privileges on the affected system and impact resources outside the vulnerable component's original security scope.

Affected Products

Qualcomm components referenced in the Qualcomm June 2026 Security Bulletin
Specific chipsets and driver versions: refer to the vendor advisory for the authoritative product list
Downstream OEM devices integrating the affected Qualcomm components

Discovery Timeline

2026-09-22 - CVE-2026-25265 published to the National Vulnerability Database
2026-09-22 - Last updated in NVD database

Technical Details for CVE-2026-25265

Vulnerability Analysis

The vulnerability stems from insecure handling of temporary files within an affected Qualcomm component. Temporary files are created with overly permissive access controls, allowing local users to read, modify, or replace file contents. When a privileged process later consumes these files, the attacker-controlled data influences privileged operations. This enables an unprivileged local user to gain elevated privileges on the target device. The scope change indicated in the CVSS assessment shows the impact reaches components beyond the immediate vulnerable process.

Root Cause

The underlying weakness maps to CWE-378: Creation of Temporary File With Insecure Permissions. The affected code path creates temporary files without applying restrictive permissions or using a secure temporary directory. Without proper permission masks or isolated storage, any local process can interact with these files during the window between creation and consumption. Secure temporary file handling requires atomic creation with O_EXCL, restrictive umask settings, and per-user private directories.

Attack Vector

Exploitation requires local access to the device and low-level user privileges. No user interaction is needed. An attacker with a shell or code execution as a normal user monitors or predicts the temporary file path, then tampers with the file before a privileged consumer reads it. Because the temporary file influences a privileged workflow, the attacker's modifications translate into elevated actions such as writing to protected files, injecting configuration, or triggering privileged code paths. Refer to the Qualcomm June 2026 Security Bulletin for component-specific technical details.

Detection Methods for CVE-2026-25265

Indicators of Compromise

Unexpected files in world-writable temporary directories such as /tmp or /data/local/tmp owned by non-privileged users but referenced by privileged services
Temporary files created with permissive modes such as 0666 or 0777 prior to being consumed by system processes
Symbolic links in temporary directories pointing to sensitive system paths or configuration files
Audit log entries showing privileged processes reading files owned or recently modified by unprivileged UIDs

Detection Strategies

Monitor process telemetry for unprivileged processes writing to file paths later opened by privileged Qualcomm services or daemons
Alert on temporary file creation with insecure permission modes within paths used by system-level components
Correlate rapid file-modification events with subsequent privilege transitions to identify race-window exploitation

Monitoring Recommendations

Enable file integrity monitoring on temporary directories consumed by privileged services
Ingest kernel audit and Android logd events into a centralized SIEM for behavioral correlation across users and processes
Track anomalous privilege escalations and new setuid or capability-elevated process launches originating from unprivileged sessions

How to Mitigate CVE-2026-25265

Immediate Actions Required

Apply the security updates listed in the Qualcomm June 2026 Security Bulletin as soon as OEM patches are available
Inventory devices using affected Qualcomm chipsets and prioritize patch deployment for high-value or shared-use endpoints
Restrict local access to trusted users and applications where feasible until patches are installed

Patch Information

Qualcomm published fixes in the June 2026 Security Bulletin. Downstream OEMs integrate these fixes into their own monthly security updates. Consult the specific device vendor for the corresponding firmware or OS build that includes the remediation.

Workarounds

Limit installation of untrusted third-party applications that could provide the local foothold required for exploitation
Enforce SELinux or equivalent mandatory access control policies in enforcing mode to constrain access to sensitive temporary paths
Where the affected component is optional, disable or remove the service until a patched build is deployed

bash

# Verify restrictive permissions on temporary directories consumed by privileged services
ls -ld /tmp /data/local/tmp
# Expected: drwxrwxrwt (sticky bit set) to prevent cross-user file tampering
chmod +t /path/to/temp_dir

# Audit for insecurely created temporary files
find /tmp -type f -perm /o+w -printf '%p %m %u\n'