How severe is CVE-2026-31717?

CVE-2026-31717 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-31717 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-31717?

CVE-2026-31717 primarily affects Linux Linux Kernel. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-31717?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-31717 have an EU (EUVD) identifier?

Yes. CVE-2026-31717 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26526.

When was CVE-2026-31717 published?

CVE-2026-31717 was published on 2026-05-01 and last updated on 2026-06-17.

CVE-2026-31717

CVE-2026-31717 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26526
Affected product: Linux Linux Kernel
Published: 2026-05-01
Last modified: 2026-06-17

Description

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 durable_owner structure to ksmbd_file to store the original opener's UID, GID, and account name. and catpure the owner information when a file handle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner() to validate the identity of the requester during SMB2_CREATE (DHnC).

Frequently asked questions

What is CVE-2026-31717?: 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 durable_owner structure to ksmbd_file to store the original opener's UID, GID, and account name. and catpure the owner information when a file handle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner() to validate the identity of the requester during SMB2_CREATE (DHnC).
How severe is CVE-2026-31717?: CVE-2026-31717 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-31717 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-31717?: CVE-2026-31717 primarily affects Linux Linux Kernel. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-31717?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-31717 have an EU (EUVD) identifier?: Yes. CVE-2026-31717 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26526.
When was CVE-2026-31717 published?: CVE-2026-31717 was published on 2026-05-01 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*

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