CVE-2025-38191
Analyzed Analyzed - Analysis Complete
BaseFortify

Publication date: 2025-07-04

Last updated on: 2025-12-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix null pointer dereference in destroy_previous_session If client set ->PreviousSessionId on kerberos session setup stage, NULL pointer dereference error will happen. Since sess->user is not set yet, It can pass the user argument as NULL to destroy_previous_session. sess->user will be set in ksmbd_krb5_authenticate(). So this patch move calling destroy_previous_session() after ksmbd_krb5_authenticate().
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Meta Information
Published
2025-07-04
Last Modified
2025-12-18
Generated
2026-05-07
AI Q&A
2025-07-04
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 7 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 5.15 (inc) to 6.1.142 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.95 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.35 (exc)
linux linux_kernel From 6.13 (inc) to 6.15.4 (exc)
linux linux_kernel 6.16
linux linux_kernel 6.16
debian debian_linux 11.0
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a null pointer dereference in the Linux kernel's ksmbd component. It occurs when a client sets the PreviousSessionId during the Kerberos session setup stage. Because the session's user field (sess->user) is not set yet, the function destroy_previous_session() is called with a NULL user argument, leading to a null pointer dereference error. The fix involves moving the call to destroy_previous_session() until after the user is set in ksmbd_krb5_authenticate().


How can this vulnerability impact me? :

This vulnerability can cause a null pointer dereference in the Linux kernel, which may lead to a kernel crash or denial of service when handling Kerberos session setups in ksmbd. This could disrupt services relying on the kernel's SMB daemon, potentially affecting system stability and availability.


What immediate steps should I take to mitigate this vulnerability?

Apply the patch that fixes the null pointer dereference in the ksmbd component of the Linux kernel by ensuring that destroy_previous_session() is called only after ksmbd_krb5_authenticate() has set sess->user. Updating the Linux kernel to a version that includes this fix is recommended.


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