CVE-2026-68253 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/i915/hdcp: check streams[] bounds before overflow
The data->streams[] overflow check is done after the buffer overflow has
already happened. Move the overflow check before the write.
Side note, emitting a warning splat with a backtrace might be overkill here, but prefer not changing the behaviour other than not doing the overrun.
Discovered using AI-assisted static analysis confirmed by Intel Product Security.
(cherry picked from commit 9284ab3b6e776c315883ac2611283d263c9460fd)
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability in question affects the drm/i915/hdcp subsystem within the Linux kernel, specifically addressing a critical buffer overflow condition that could potentially lead to system instability or privilege escalation. This issue resides in the Intel Graphics driver component responsible for handling high-definition content protection mechanisms. The flaw manifests when processing HDCP (High-bandwidth Digital Content Protection) streams, where the kernel fails to validate array bounds before performing memory writes to the data->streams[] buffer structure.
The technical implementation of this vulnerability stems from improper order of operations in the validation logic. According to the patch description, the overflow check occurs after the buffer overflow has already taken place, meaning that malicious input could potentially overwrite adjacent memory locations before any bounds verification occurs. This timing issue creates an exploitable condition where an attacker could craft specific HDCP stream data that triggers the out-of-bounds write operation. The vulnerability aligns with CWE-129, which describes improper validation of array indices, and represents a classic case of inadequate input sanitization leading to memory corruption.
The operational impact of this vulnerability extends beyond simple buffer overflows as it affects the integrity of the graphics subsystem during content protection operations. When exploited successfully, such a condition could allow an attacker with local privileges to corrupt kernel memory structures, potentially leading to denial of service conditions or more severe exploitation scenarios. The affected subsystem handles HDCP stream management for Intel graphics hardware, making this particularly concerning for systems that rely on content protection mechanisms for multimedia applications and digital rights management.
Mitigation strategies should focus on implementing proper bounds checking prior to any memory write operations within the HDCP processing pipeline. The recommended fix involves reordering the validation logic to ensure that array boundary checks occur before any buffer modifications take place. Security practitioners should also consider implementing additional runtime protections such as kernel address space layout randomization and stack canaries where applicable. Given that this vulnerability was discovered through AI-assisted static analysis and confirmed by Intel Product Security, organizations should prioritize applying the relevant kernel patches while monitoring for potential exploitation attempts in their environments.
The vulnerability demonstrates a pattern commonly observed in kernel security issues where defensive programming practices are insufficient due to improper execution flow ordering. This particular flaw could potentially map to ATT&CK technique T1068, which involves privilege escalation through local exploits, though the initial access vector would likely be through legitimate system interfaces rather than direct malicious code injection. Organizations should also consider implementing network-based intrusion detection systems that monitor for anomalous HDCP-related kernel activity patterns that might indicate exploitation attempts.