CVE-2026-31717: ksmbd: validate owner of durable handle on reconnect
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate owner of durable handle on reconnect
Currently, ksmbd does not verify if the user attempting to reconnect to a durable handle is the same user who originally opened the file. This allows any authenticated user to hijack an orphaned durable handle by predicting or brute-forcing the persistent ID.
According to MS-SMB2, the server MUST verify that the SecurityContext of the reconnect request matches the SecurityContext associated with the existing open. Add a durableowner structure to ksmbdfile to store the original opener's UID, GID, and account name. and catpure the owner information when a file handle becomes orphaned. and implementing ksmbdvfscomparedurableowner() to validate the identity of the requester during SMB2CREATE (DHnC).
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-31717?
The severity of CVE-2026-31717 is classified as medium due to potential unauthorized access risks.
How do I fix CVE-2026-31717?
To fix CVE-2026-31717, you should apply the latest patches or updates provided for the ksmbd component of the Linux kernel.
What systems are affected by CVE-2026-31717?
CVE-2026-31717 affects systems utilizing the ksmbd service in the Linux kernel.
What are the potential risks associated with CVE-2026-31717?
The potential risks associated with CVE-2026-31717 include unauthorized access to file shares and data manipulation.
Is there a workaround for CVE-2026-31717?
As an interim measure, restricting access to ksmbd services can reduce the risk associated with CVE-2026-31717 until a patch is applied.