CVE-2026-93069 in Linux
Summary
by MITRE • 09/17/2026
In the Linux kernel, the following vulnerability has been resolved:
OPP: Fix cleanup ordering
Commit 173e02d67494 ("OPP: Initialize scope-based pointers inline") added initialization for all pointers. In some cases, the ordering was changed so that *opp_table was initialized after *opp. This also changes the order of the registered cleanup functions.
When the cleanup happens, this can cause use-after-free errors when the last reference is released and the release function _opp_kref_release tries to access the already freed opp->opp_table.
Initialize *opp_table before *opp again to fix this and ensure the correct cleanup order.
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Analysis
by VulDB Data Team • 09/18/2026
The Linux kernel's Operating Performance Points subsystem manages power management policies by regulating CPU frequency and voltage levels based on system load and thermal constraints. A recent resolution addressed a critical initialization ordering flaw within this subsystem, specifically involving the relationship between opp_table structures representing hardware performance states and individual opp entries describing specific operating points. The vulnerability originated from commit 173e02d67494 which aimed to improve code clarity by initializing scope-based pointers inline during structure allocation. While well-intentioned for readability, this refactoring inadvertently altered the sequence in which critical data structures were populated relative to their associated cleanup handlers registered via kernel resource management APIs such as devm_kzalloc or similar managed memory functions that attach automatic release callbacks upon allocation failure or device detachment scenarios.
The core technical flaw lies in a use-after-free condition triggered during reference counting operations when an opp object is released. In the corrected implementation, the opp_table pointer within each individual opp structure must be initialized before the opp entry itself to ensure proper dependency resolution during teardown sequences. When the ordering was inverted due to the previous patch, cleanup routines executed in an incorrect sequence where the release function _opp_kref_release attempted to dereference the opp->opp_table member after that table had already been freed by earlier cleanup steps. This race condition between resource deallocation and dependent object access constitutes a classic memory safety violation allowing potential kernel panic or arbitrary code execution depending on heap layout conditions at runtime.
From an industry standards perspective, this vulnerability maps directly to CWE-416 Use After Free which describes situations where program continues using pointer after it has been freed leading undefined behavior potentially exploitable for privilege escalation if attacker controls allocation patterns nearby in memory space Additionally ATT&CK technique T1059 Command and Scripting Interpreter may be relevant indirectly since successful exploitation could allow attackers inject malicious commands through compromised kernel modules loaded post-exploitation phase though primary impact remains stability degradation rather than direct remote code execution vector without additional context about surrounding subsystems involved.
Operational impacts include system instability manifesting as random crashes particularly under heavy dynamic frequency scaling workloads where frequent creation and destruction of opp structures occurs during thermal throttling events or performance state transitions administrators monitoring dmesg logs would observe NULL pointer dereference traces originating from OPP core code paths confirming presence issue before patch applied mitigation strategy involves applying upstream kernel update containing fix ensuring correct initialization order preserved throughout lifecycle management operations involving these power management data structures organizations running affected versions should prioritize deployment especially those deploying servers desktops embedded devices relying heavily adaptive performance scaling features maintain regular security updates schedule monitor vendor advisories closely track progress toward stable release incorporating fixes addressing identified weaknesses promptly minimize exposure window potential attackers attempting exploit similar flaws elsewhere within same subsystem family