{"api_version":"1","generated_at":"2026-04-22T17:47:51+00:00","cve":"CVE-2026-31392","urls":{"html":"https://cve.report/CVE-2026-31392","api":"https://cve.report/api/cve/CVE-2026-31392.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-31392","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-31392"},"summary":{"title":"smb: client: fix krb5 mount with username option","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix krb5 mount with username option\n\nCustomer reported that some of their krb5 mounts were failing against\na single server as the client was trying to mount the shares with\nwrong credentials.  It turned out the client was reusing SMB session\nfrom first mount to try mounting the other shares, even though a\ndifferent username= option had been specified to the other mounts.\n\nBy using username mount option along with sec=krb5 to search for\nprincipals from keytab is supported by cifs.upcall(8) since\ncifs-utils-4.8.  So fix this by matching username mount option in\nmatch_session() even with Kerberos.\n\nFor example, the second mount below should fail with -ENOKEY as there\nis no 'foobar' principal in keytab (/etc/krb5.keytab).  The client\nends up reusing SMB session from first mount to perform the second\none, which is wrong.\n\n```\n$ ktutil\nktutil:  add_entry -password -p testuser -k 1 -e aes256-cts\nPassword for testuser@ZELDA.TEST:\nktutil:  write_kt /etc/krb5.keytab\nktutil:  quit\n$ klist -ke\nKeytab name: FILE:/etc/krb5.keytab\nKVNO Principal\n ---- ----------------------------------------------------------------\n   1 testuser@ZELDA.TEST (aes256-cts-hmac-sha1-96)\n$ mount.cifs //w22-root2/scratch /mnt/1 -o sec=krb5,username=testuser\n$ mount.cifs //w22-root2/scratch /mnt/2 -o sec=krb5,username=foobar\n$ mount -t cifs | grep -Po 'username=\\K\\w+'\ntestuser\ntestuser\n```","state":"PUBLISHED","assigner":"Linux","published_at":"2026-04-03 16:16:37","updated_at":"2026-04-07 13:20:55"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/fd4547830720647d4af02ee50f883c4b1cca06e4","name":"https://git.kernel.org/stable/c/fd4547830720647d4af02ee50f883c4b1cca06e4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d33cbf0bf8979d779900da9be2505d68d9d8da25","name":"https://git.kernel.org/stable/c/d33cbf0bf8979d779900da9be2505d68d9d8da25","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6e9ff1eb7feedcf46ff2d0503759960ab58e7775","name":"https://git.kernel.org/stable/c/6e9ff1eb7feedcf46ff2d0503759960ab58e7775","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/12b4c5d98cd7ca46d5035a57bcd995df614c14e1","name":"https://git.kernel.org/stable/c/12b4c5d98cd7ca46d5035a57bcd995df614c14e1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9ee803bfdba0cf739038dbdabdd4c02582c8f2b2","name":"https://git.kernel.org/stable/c/9ee803bfdba0cf739038dbdabdd4c02582c8f2b2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2","name":"https://git.kernel.org/stable/c/9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-31392","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31392","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4ff67b720c02c36e54d55b88c2931879b7db1cd2 fd4547830720647d4af02ee50f883c4b1cca06e4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4ff67b720c02c36e54d55b88c2931879b7db1cd2 9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4ff67b720c02c36e54d55b88c2931879b7db1cd2 d33cbf0bf8979d779900da9be2505d68d9d8da25 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4ff67b720c02c36e54d55b88c2931879b7db1cd2 9ee803bfdba0cf739038dbdabdd4c02582c8f2b2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4ff67b720c02c36e54d55b88c2931879b7db1cd2 6e9ff1eb7feedcf46ff2d0503759960ab58e7775 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4ff67b720c02c36e54d55b88c2931879b7db1cd2 12b4c5d98cd7ca46d5035a57bcd995df614c14e1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 223c7f082d2836ac719b3b228bdcfab35e5e5330 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 88720224330a655ab6268e20109b65b11cfd7f6a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.36","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.36 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.167 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.130 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.78 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.20 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.10 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0-rc5 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"31392","cve":"CVE-2026-31392","epss":"0.000240000","percentile":"0.066190000","score_date":"2026-04-07","updated_at":"2026-04-08 00:03:39"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/smb/client/connect.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"fd4547830720647d4af02ee50f883c4b1cca06e4","status":"affected","version":"4ff67b720c02c36e54d55b88c2931879b7db1cd2","versionType":"git"},{"lessThan":"9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2","status":"affected","version":"4ff67b720c02c36e54d55b88c2931879b7db1cd2","versionType":"git"},{"lessThan":"d33cbf0bf8979d779900da9be2505d68d9d8da25","status":"affected","version":"4ff67b720c02c36e54d55b88c2931879b7db1cd2","versionType":"git"},{"lessThan":"9ee803bfdba0cf739038dbdabdd4c02582c8f2b2","status":"affected","version":"4ff67b720c02c36e54d55b88c2931879b7db1cd2","versionType":"git"},{"lessThan":"6e9ff1eb7feedcf46ff2d0503759960ab58e7775","status":"affected","version":"4ff67b720c02c36e54d55b88c2931879b7db1cd2","versionType":"git"},{"lessThan":"12b4c5d98cd7ca46d5035a57bcd995df614c14e1","status":"affected","version":"4ff67b720c02c36e54d55b88c2931879b7db1cd2","versionType":"git"},{"status":"affected","version":"223c7f082d2836ac719b3b228bdcfab35e5e5330","versionType":"git"},{"status":"affected","version":"88720224330a655ab6268e20109b65b11cfd7f6a","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/smb/client/connect.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.36"},{"lessThan":"2.6.36","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.167","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.130","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.78","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.20","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0-rc5","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.167","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.130","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.78","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.20","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.10","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0-rc5","versionStartIncluding":"2.6.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.32.44","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34.12","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix krb5 mount with username option\n\nCustomer reported that some of their krb5 mounts were failing against\na single server as the client was trying to mount the shares with\nwrong credentials.  It turned out the client was reusing SMB session\nfrom first mount to try mounting the other shares, even though a\ndifferent username= option had been specified to the other mounts.\n\nBy using username mount option along with sec=krb5 to search for\nprincipals from keytab is supported by cifs.upcall(8) since\ncifs-utils-4.8.  So fix this by matching username mount option in\nmatch_session() even with Kerberos.\n\nFor example, the second mount below should fail with -ENOKEY as there\nis no 'foobar' principal in keytab (/etc/krb5.keytab).  The client\nends up reusing SMB session from first mount to perform the second\none, which is wrong.\n\n```\n$ ktutil\nktutil:  add_entry -password -p testuser -k 1 -e aes256-cts\nPassword for testuser@ZELDA.TEST:\nktutil:  write_kt /etc/krb5.keytab\nktutil:  quit\n$ klist -ke\nKeytab name: FILE:/etc/krb5.keytab\nKVNO Principal\n ---- ----------------------------------------------------------------\n   1 testuser@ZELDA.TEST (aes256-cts-hmac-sha1-96)\n$ mount.cifs //w22-root2/scratch /mnt/1 -o sec=krb5,username=testuser\n$ mount.cifs //w22-root2/scratch /mnt/2 -o sec=krb5,username=foobar\n$ mount -t cifs | grep -Po 'username=\\K\\w+'\ntestuser\ntestuser\n```"}],"providerMetadata":{"dateUpdated":"2026-04-06T06:59:50.319Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/fd4547830720647d4af02ee50f883c4b1cca06e4"},{"url":"https://git.kernel.org/stable/c/9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2"},{"url":"https://git.kernel.org/stable/c/d33cbf0bf8979d779900da9be2505d68d9d8da25"},{"url":"https://git.kernel.org/stable/c/9ee803bfdba0cf739038dbdabdd4c02582c8f2b2"},{"url":"https://git.kernel.org/stable/c/6e9ff1eb7feedcf46ff2d0503759960ab58e7775"},{"url":"https://git.kernel.org/stable/c/12b4c5d98cd7ca46d5035a57bcd995df614c14e1"}],"title":"smb: client: fix krb5 mount with username option","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-31392","datePublished":"2026-04-03T15:15:57.491Z","dateReserved":"2026-03-09T15:48:24.085Z","dateUpdated":"2026-04-06T06:59:50.319Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-04-03 16:16:37","lastModifiedDate":"2026-04-07 13:20:55","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"31392","Ordinal":"1","Title":"smb: client: fix krb5 mount with username option","CVE":"CVE-2026-31392","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"31392","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix krb5 mount with username option\n\nCustomer reported that some of their krb5 mounts were failing against\na single server as the client was trying to mount the shares with\nwrong credentials.  It turned out the client was reusing SMB session\nfrom first mount to try mounting the other shares, even though a\ndifferent username= option had been specified to the other mounts.\n\nBy using username mount option along with sec=krb5 to search for\nprincipals from keytab is supported by cifs.upcall(8) since\ncifs-utils-4.8.  So fix this by matching username mount option in\nmatch_session() even with Kerberos.\n\nFor example, the second mount below should fail with -ENOKEY as there\nis no 'foobar' principal in keytab (/etc/krb5.keytab).  The client\nends up reusing SMB session from first mount to perform the second\none, which is wrong.\n\n```\n$ ktutil\nktutil:  add_entry -password -p testuser -k 1 -e aes256-cts\nPassword for testuser@ZELDA.TEST:\nktutil:  write_kt /etc/krb5.keytab\nktutil:  quit\n$ klist -ke\nKeytab name: FILE:/etc/krb5.keytab\nKVNO Principal\n ---- ----------------------------------------------------------------\n   1 testuser@ZELDA.TEST (aes256-cts-hmac-sha1-96)\n$ mount.cifs //w22-root2/scratch /mnt/1 -o sec=krb5,username=testuser\n$ mount.cifs //w22-root2/scratch /mnt/2 -o sec=krb5,username=foobar\n$ mount -t cifs | grep -Po 'username=\\K\\w+'\ntestuser\ntestuser\n```","Type":"Description","Title":"smb: client: fix krb5 mount with username option"}]}}}