CVE-2023-53550 in Linux
Summary
by MITRE • 10/04/2025
In the Linux kernel, the following vulnerability has been resolved:
cpufreq: amd-pstate: fix global sysfs attribute type
In commit 3666062b87ec ("cpufreq: amd-pstate: move to use bus_get_dev_root()") the "amd_pstate" attributes where moved from a dedicated kobject to the cpu root kobject.
While the dedicated kobject expects to contain kobj_attributes the root kobject needs device_attributes.
As the changed arguments are not used by the callbacks it works most of the time. However CFI will detect this issue:
[ 4947.849350] CFI failure at dev_attr_show+0x24/0x60 (target: show_status+0x0/0x70; expected type: 0x8651b1de)
... [ 4947.849409] Call Trace:
[ 4947.849410] <TASK>
[ 4947.849411] ? __warn+0xcf/0x1c0
[ 4947.849414] ? dev_attr_show+0x24/0x60
[ 4947.849415] ? report_cfi_failure+0x4e/0x60
[ 4947.849417] ? handle_cfi_failure+0x14c/0x1d0
[ 4947.849419] ? __cfi_show_status+0x10/0x10
[ 4947.849420] ? handle_bug+0x4f/0x90
[ 4947.849421] ? exc_invalid_op+0x1a/0x60
[ 4947.849422] ? asm_exc_invalid_op+0x1a/0x20
[ 4947.849424] ? __cfi_show_status+0x10/0x10
[ 4947.849425] ? dev_attr_show+0x24/0x60
[ 4947.849426] sysfs_kf_seq_show+0xa6/0x110
[ 4947.849433] seq_read_iter+0x16c/0x4b0
[ 4947.849436] vfs_read+0x272/0x2d0
[ 4947.849438] ksys_read+0x72/0xe0
[ 4947.849439] do_syscall_64+0x76/0xb0
[ 4947.849440] ? do_user_addr_fault+0x252/0x650
[ 4947.849442] ? exc_page_fault+0x7a/0x1b0
[ 4947.849443] entry_SYSCALL_64_after_hwframe+0x72/0xdc
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Analysis
by VulDB Data Team • 03/02/2026
The vulnerability CVE-2023-53550 affects the Linux kernel's cpufreq subsystem specifically within the amd-pstate driver implementation. This issue stems from an improper attribute type assignment when migrating cpu frequency management attributes from a dedicated kobject to the cpu root kobject. The problem manifests during the transition from commit 3666062b87ec which restructured how amd-pstate attributes are organized within the kernel's sysfs interface. When attributes are moved from a dedicated kobject that expects kobj_attributes to a root kobject that requires device_attributes, a type mismatch occurs that can trigger control flow integrity (CFI) violations.
The technical flaw lies in the fundamental incompatibility between two different attribute types within the kernel's device model infrastructure. The dedicated kobject uses kobj_attribute structures while the cpu root kobject requires device_attribute structures, despite both serving similar purposes in exposing cpu frequency information through sysfs. Although the callback functions themselves do not utilize the attribute type information, the CFI mechanism performs strict type checking during runtime execution. This checking occurs when sysfs operations attempt to read the attributes through the dev_attr_show function, which expects a specific attribute type but receives an incompatible one. The CFI failure is evident in the call trace showing dev_attr_show attempting to access show_status with an unexpected type identifier 0x8651b1de, indicating a mismatch between expected and actual function signatures or attribute structures.
The operational impact of this vulnerability is primarily relevant in environments where Control Flow Integrity is enabled, which is increasingly common in modern kernel security configurations. Systems running with CFI active will experience crashes or kernel panics when attempting to read the affected cpu frequency attributes through sysfs interfaces. This prevents legitimate monitoring and control of cpu frequency scaling behavior on AMD processors using the amd-pstate driver, potentially disrupting system management operations and performance tuning activities. The vulnerability does not represent a direct security exploit but rather a kernel stability issue that can be leveraged by attackers to cause denial of service conditions or potentially escalate privileges through system instability.
Mitigation strategies for this vulnerability involve applying the official kernel patch that corrects the attribute type assignment during the kobject migration process. The fix ensures that when attributes are moved to the cpu root kobject, they are properly cast or restructured to use device_attribute types rather than kobj_attribute types. Organizations should prioritize updating their kernel versions to include this patch, particularly in production environments where CFI is enabled. System administrators should also monitor for kernel panics or instability related to cpu frequency management when applying updates, as the transition may require careful validation. The vulnerability aligns with CWE-691, which addresses inadequate control flow protection mechanisms, and could potentially be categorized under ATT&CK technique T1499.001 for resource hijacking through system instability. Regular kernel updates and security monitoring remain essential practices for maintaining system integrity and preventing exploitation of such low-level kernel vulnerabilities.