Answer in brief
CVE-2026-31392 records a High severity (CVSS 8.1) vulnerability in smb: client: fix krb5 mount with username option. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=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 | fd4547830720647d4af02ee50f883c4b1cca06e4, 9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2, d33cbf0bf8979d779900da9be2505d68d9d8da25, 9ee803bfdba0cf739038dbdabdd4c02582c8f2b2, 6e9ff1eb7feedcf46ff2d0503759960ab58e7775, 12b4c5d98cd7ca46d5035a57bcd995df614c14e1, 2.6.33, 2.6.35 |
| Linux/Linuxgeneric | 2.6.36 | Not reported |
Published upstream
Apr 3, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 16, 2026
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 fix this by matching username mount option in match_session() even with Kerberos. For example, the second mount below should fail with -ENOKEY as there is no 'foobar' principal in keytab (/etc/krb5.keytab). The client ends up reusing SMB session from first mount to perform the second one, which is wrong. ``` $ ktutil ktutil: add_entry -password -p testuser -k 1 -e aes256-cts Password for [email protected]: ktutil: write_kt /etc/krb5.keytab ktutil: quit $ klist -ke Keytab name: FILE:/etc/krb5.keytab KVNO Principal ---- ---------------------------------------------------------------- 1 [email protected] (aes256-cts-hmac-sha1-96) $ mount.cifs //w22-root2/scratch /mnt/1 -o sec=krb5,username=testuser $ mount.cifs //w22-root2/scratch /mnt/2 -o sec=krb5,username=foobar $ mount -t cifs | grep -Po 'username=\K\w+' testuser testuser ```
Quoted source text, attributed separately from HOL analysis.