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CVE-2026-31392

Vulnérabilité élevée dans Linux (Linux)

CVSS 8.1 · Élevée
EPSS 0.2%
Linux•Linux•Versions : <9ee803bfdba0cf739038dbdabdd4c02582c8f2b2, <=6.1.*, <=6.12.*, 6.12.78, 2.6.32.44, 2.6.34.12, 4ff67b720c02c36e54d55b88c2931879b7db1cd2, 0, 7.0, 2.6.36, <6e9ff1eb7feedcf46ff2d0503759960ab58e7775, <fd4547830720647d4af02ee50f883c4b1cca06e4, <9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2, <=6.6.*, <=6.19.*, <12b4c5d98cd7ca46d5035a57bcd995df614c14e1, <2.6.33, <=6.18.*, <2.6.36, <2.6.35, 6.1.167, <d33cbf0bf8979d779900da9be2505d68d9d8da25, <=*, 6.19.10, 6.6.130, 88720224330a655ab6268e20109b65b11cfd7f6a, 6.18.20, 223c7f082d2836ac719b3b228bdcfab35e5e5330

Description

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 testuser@ZELDA.TEST: ktutil: write_kt /etc/krb5.keytab ktutil: quit $ klist -ke Keytab name: FILE:/etc/krb5.keytab KVNO Principal ---- ---------------------------------------------------------------- 1 testuser@ZELDA.TEST (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 ```

Gravité et risque d'exploitation

CVE-2026-31392 obtient un score CVSS de 8.1/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.18 %, ce qui la place devant 6.9 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <9ee803bfdba0cf739038dbdabdd4c02582c8f2b2, <=6.1.*, <=6.12.*, 6.12.78, 2.6.32.44, 2.6.34.12, 4ff67b720c02c36e54d55b88c2931879b7db1cd2, 0, 7.0, 2.6.36, <6e9ff1eb7feedcf46ff2d0503759960ab58e7775, <fd4547830720647d4af02ee50f883c4b1cca06e4, <9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2, <=6.6.*, <=6.19.*, <12b4c5d98cd7ca46d5035a57bcd995df614c14e1, <2.6.33, <=6.18.*, <2.6.36, <2.6.35, 6.1.167, <d33cbf0bf8979d779900da9be2505d68d9d8da25, <=*, 6.19.10, 6.6.130, 88720224330a655ab6268e20109b65b11cfd7f6a, 6.18.20, 223c7f082d2836ac719b3b228bdcfab35e5e5330) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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