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Review reviewHigh

CVE-2026-31392

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix krb5 mount with username option Customer reported that some of their krb5 mounts were failing against a single server as the client was trying to mount the shares with wrong credentials. It turned out the client was reusing SMB session from first mount to try mounting the other shares, even though a different username= option had been specified to the other mounts. By using username mount option along with sec=krb5 to search for principals from keytab is supported by cifs.upcall(8) since cifs-utils-4.8. So...

CVSS
8.1
EPSS
0.12%
2.36% percentile
CISA KEV
Not listed
Published
2026.04.04
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.12%
Technical severityCVSS 8.1

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix krb5 mount with username option Customer reported that some of their krb5 mounts were failing against a single server as the client was trying to mount the shares with wrong credentials. It turned out the client was reusing SMB session from first mount to try mounting the other shares, even though a different username= option had been specified to the other mounts. By using username mount option along with sec=krb5 to search for principals from keytab is supported by cifs.upcall(8) since cifs-utils-4.8. So...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < fd4547830720647d4af02ee50f883c4b1cca06e4, >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < 9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2, >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < d33cbf0bf8979d779900da9be2505d68d9d8da25, >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < 9ee803bfdba0cf739038dbdabdd4c02582c8f2b2, >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < 6e9ff1eb7feedcf46ff2d0503759960ab58e7775, >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < 12b4c5d98cd7ca46d5035a57bcd995df614c14e1, >= 223c7f082d2836ac719b3b228bdcfab35e5e5330, >= 88720224330a655ab6268e20109b65b11cfd7f6a, >= 2.6.32.44 < 2.6.33, >= 2.6.34.12 < 2.6.35, >= 2.6.36, >= 2.6.36 < 6.1.167, >= 6.2 < 6.6.130, >= 6.7 < 6.12.78, >= 6.13 < 6.18.20, >= 6.19 < 6.19.10, 7.0
Fixed versions
2.6.33, 2.6.35, 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L
CWE
Not available
CVE-2026-31392 — Linux Linux, linux kernel | SECUFOCUS NOW