Summary
In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - Always pass in...
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:
__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.
Impact
The application dereferences a null pointer, causing a crash. Typical impact: denial of service via crash.
CVE-2025-39936 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-39936? CVE-2025-39936 is a medium-severity null pointer dereference vulnerability. No fixed version is listed yet. The application dereferences a null pointer, causing a crash.
- How severe is CVE-2025-39936? CVE-2025-39936 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-39936? No fixed version is listed for CVE-2025-39936 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-39936 exploitable, and should I be worried? Whether CVE-2025-39936 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-39936 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.