8.8

CVE-2026-31717: ksmbd: validate owner of durable handle on reconnect

Modified
AliasesUBUNTU-CVE-2026-31717DEBIAN-CVE-2026-31717CGA-25x3-4vh4-q66f
Published 01-05-2026Last modified 05-08-2026

Vulnerability summary

CVE-2026-31717 is a high (CVSS 8.8) vulnerability in linux. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 38% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 8.8, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
8.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.44%
0%100%
Low · -0.16 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 6 · Related 7
OPENSUSE-SU-2026:10793-1USN-8488-1USN-8488-2USN-8507-1USN-8569-1USN-8603-1

Timeline

  1. 01-05-2026
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

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).

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.44%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

Decrease -0.16 pp

From 0.60% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu110 products
  • linuxAll versions (No fix recorded) | < 7.0.0-27.27
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 7.0.0-1008.8
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Chainguard11 products
  • linux-aws-6.12< 6.12.85-r2
  • linux-aws-6.18< 6.18.31-r0
  • linux-azure-6.12< 6.12.85-r2
  • linux-azure-6.18< 6.18.24-r1 | < 6.18.31-r0
  • linux-gcp-6.12All versions (No fix recorded)
Linux2 products
  • linux≥ 8df4bcdb0a4232192b2445256c39b787d58ef14d, < 712cdf917e77a6444ce3836874829d770db20ee6 | ≥ c8efcc786146a951091588e5fa7e3c754850cb3c, < c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d | ≥ c8efcc786146a951091588e5fa7e3c754850cb3c, < 00ce8d6789dae72d042a4522264964c72891ca37 | ≥ c8efcc786146a951091588e5fa7e3c754850cb3c, < c908c853f304a4969b5aa10eba0b50350cc65b80 | ≥ c8efcc786146a951091588e5fa7e3c754850cb3c, < 49110a8ce654bbe56bef7c5e44cce31f4b102b8a | ≥ 6.6.32, < 6.6.142 | 6.9
  • linux_kernel≥ 6.6.32, < 6.7 | ≥ 6.9, < 6.18.25 | ≥ 6.19, < 7.0.2 | 7.1:rc1
Debian1 product
  • linux< 6.12.94-1 | < 7.0.3-1

4 vendors · 124 products

References

17 links
Show all 17 references