Linux Kernel up to 6.16.8 __sev_platform_shutdown_locked null pointer dereference

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 6.16.8. This affects the function __sev_platform_shutdown_locked. Performing a manipulation results in an unknown weakness. This vulnerability is reported as CVE-2025-39936. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.16.8. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - Always pass in an error pointer to __sev_platform_shutdown_locked() When 9770b428b1a2 ("crypto: ccp - Move dev_info/err messages for SEV/SNP init and shutdown") moved the error messages dumping so that they don't need to be issued by the callers, it missed the case where __sev_firmware_shutdown() calls __sev_platform_shutdown_locked() with a NULL argument which leads to a NULL ptr deref on the shutdown path, during suspend to disk: #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 983 Comm: hib.sh Not tainted 6.17.0-rc4+ #1 PREEMPT(voluntary) Hardware name: Supermicro Super Server/H12SSL-i, BIOS 2.5 09/08/2022 RIP: 0010:__sev_platform_shutdown_locked.cold+0x0/0x21 [ccp] That rIP is: 00000000000006fd <__sev_platform_shutdown_locked.cold>: 6fd: 8b 13 mov (%rbx),%edx 6ff: 48 8b 7d 00 mov 0x0(%rbp),%rdi 703: 89 c1 mov %eax,%ecx Code: 74 05 31 ff 41 89 3f 49 8b 3e 89 ea 48 c7 c6 a0 8e 54 a0 41 bf 92 ff ff ff e8 e5 2e 09 e1 c6 05 2a d4 38 00 01 e9 26 af ff ff <8b> 13 48 8b 7d 00 89 c1 48 c7 c6 18 90 54 a0 89 44 24 04 e8 c1 2e RSP: 0018:ffffc90005467d00 EFLAGS: 00010282 RAX: 00000000ffffff92 RBX: 0000000000000000 RCX: 0000000000000000 ^^^^^^^^^^^^^^^^ and %rbx is nice and clean. Call Trace: <TASK> __sev_firmware_shutdown.isra.0 sev_dev_destroy psp_dev_destroy sp_destroy pci_device_shutdown device_shutdown kernel_power_off hibernate.cold state_store kernfs_fop_write_iter vfs_write ksys_write do_syscall_64 entry_SYSCALL_64_after_hwframe Pass in a pointer to the function-local error var in the caller. With that addressed, suspending the ccp shows the error properly at least: ccp 0000:47:00.1: sev command 0x2 timed out, disabling PSP ccp 0000:47:00.1: SEV: failed to SHUTDOWN error 0x0, rc -110 SEV-SNP: Leaking PFN range 0x146800-0x146a00 SEV-SNP: PFN 0x146800 unassigned, dumping non-zero entries in 2M PFN region: [0x146800 - 0x146a00] ... ccp 0000:47:00.1: SEV-SNP firmware shutdown failed, rc -16, error 0x0 ACPI: PM: Preparing to enter system sleep state S5 kvm: exiting hardware virtualization reboot: Power down Btw, this driver is crying to be cleaned up to pass in a proper I/O struct which can be used to store information between the different functions, otherwise stuff like that will happen in the future again.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-39936 since 04/16/2025. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 6.16.9 eliminates this vulnerability. Applying the patch bc509293c9d4f4f74e776f4a0bbb61f63c041938/46834d90a9a13549264b9581067d8f746b4b36cc is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2025-2194). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Google Cloud Platform
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux
• NetApp ActiveIQ Unified Manager
• IBM QRadar SIEM
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.16.0
• 6.16.1
• 6.16.2
• 6.16.3
• 6.16.4
• 6.16.5
• 6.16.6
• 6.16.7
• 6.16.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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