CVE-2026-31392
published 2026-04-03CVE-2026-31392: 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…
PriorityP339high8.1CVSS 3.1
AVLACLPRHUINSCCHIHAL
EPSS
0.12%
2.4th percentile
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
```
Affected
47 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 6.19.10-1 (forky) | linux 6.19.10-1 (forky) |
| linux | linux | — | — |
| linux | linux | — | — |
| linux | linux | — | — |
| linux | linux | >= 2.6.32.44 < 2.6.33 | 2.6.33 |
| linux | linux | >= 2.6.34.12 < 2.6.35 | 2.6.35 |
| linux | linux | >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < fd4547830720647d4af02ee50f883c4b1cca06e4 | fd4547830720647d4af02ee50f883c4b1cca06e4 |
| linux | linux | >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < 9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2 | 9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2 |
| linux | linux | >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < d33cbf0bf8979d779900da9be2505d68d9d8da25 | d33cbf0bf8979d779900da9be2505d68d9d8da25 |
| linux | linux | >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < 9ee803bfdba0cf739038dbdabdd4c02582c8f2b2 | 9ee803bfdba0cf739038dbdabdd4c02582c8f2b2 |
| linux | linux | >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < 6e9ff1eb7feedcf46ff2d0503759960ab58e7775 | 6e9ff1eb7feedcf46ff2d0503759960ab58e7775 |
| linux | linux | >= 4ff67b720c02c36e54d55b88c2931879b7db1cd2 < 12b4c5d98cd7ca46d5035a57bcd995df614c14e1 | 12b4c5d98cd7ca46d5035a57bcd995df614c14e1 |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 6.19.10-1 | 6.19.10-1 |
| linux | linux_kernel | >= 2.6.32.44 < 2.6.33 | 2.6.33 |
| linux | linux_kernel | >= 2.6.34.12 < 2.6.35 | 2.6.35 |
| linux | linux_kernel | >= 2.6.36 < 6.1.167 | 6.1.167 |
| linux | linux_kernel | >= 6.13 < 6.18.20 | 6.18.20 |
| linux | linux_kernel | >= 6.19 < 6.19.10 | 6.19.10 |
| linux | linux_kernel | >= 6.2 < 6.6.130 | 6.6.130 |
| linux | linux_kernel | >= 6.7 < 6.12.78 | 6.12.78 |
| ubuntu | linux | — | — |
CVSS provenance
nvdv3.18.1HIGHCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L
vendor_redhat5.8MEDIUM
vendor_ubuntu2.0LOW
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Ubuntu
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Title: Linux kernel (HWE) vulnerabilities
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It was discovered that some AMD processors did not properly clear data in
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It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
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Title: Linux kernel (Azure CVM) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A l
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Linux kernel (Azure FIPS) vulnerabilities
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CVE-2026-46073 [LOW] Linux kernel (Azure FIPS) vulnerabilities
Title: Linux kernel (Azure FIPS) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A
Ubuntu
Linux kernel (Azure CVM) vulnerabilities
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CVE-2026-43129 [LOW] Linux kernel (Azure CVM) vulnerabilities
Title: Linux kernel (Azure CVM) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A l
Ubuntu
Linux kernel (Azure) vulnerabilities
vendor_ubuntu·2026-07-24·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (Azure) vulnerabilities
Title: Linux kernel (Azure) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local
Ubuntu
Linux kernel (AWS) vulnerabilities
vendor_ubuntu·2026-07-24·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (AWS) vulnerabilities
Title: Linux kernel (AWS) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local a
Ubuntu
Linux kernel (Oracle) vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (Oracle) vulnerabilities
Title: Linux kernel (Oracle) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A loca
Ubuntu
Linux kernel (NVIDIA) vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 2.0
CVE-2026-43129 [LOW] Linux kernel (NVIDIA) vulnerabilities
Title: Linux kernel (NVIDIA) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A loca
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-07-23·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local attacke
Ubuntu
Linux kernel (GCP FIPS) vulnerabilities
vendor_ubuntu·2026-07-21·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel (GCP FIPS) vulnerabilities
Title: Linux kernel (GCP FIPS) vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A lo
Ubuntu
Linux kernel vulnerabilities
vendor_ubuntu·2026-07-20·CVSS 2.0
CVE-2026-46073 [LOW] Linux kernel vulnerabilities
Title: Linux kernel vulnerabilities
Summary: Several security issues were fixed in the Linux kernel.
It was discovered that some AMD processors did not properly clear data in
the floating point divider unit during speculative execution. A local
attacker could use this to expose sensitive information. (CVE-2025-54505)
It was discovered that some AMD Zen 2 processors did not properly isolate
shared resources in the operation cache. A local attacker could possibly
use this issue to corrupt instructions executed at a higher privilege
level, resulting in privilege escalation. (CVE-2025-54518)
It was discovered that some AMD Zen 5 processors supporting RDSEED
instruction did not properly handle entropy, potentially resulting in the
consumption of insufficiently random values. A local attacke
Red Hat
kernel: smb: client: fix krb5 mount with username option
vendor_redhat·2026-04-03·CVSS 5.8
CVE-2026-31392 [MEDIUM] CWE-488 kernel: smb: client: fix krb5 mount with username option
kernel: smb: client: fix krb5 mount with username option
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
Debian
CVE-2026-31392: linux - In the Linux kernel, the following vulnerability has been resolved: smb: client...
vendor_debian·2026
CVE-2026-31392 CVE-2026-31392: linux - In the Linux kernel, the following vulnerability has been resolved: smb: client...
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.keyta
VulDB
Linux Kernel up to 7.0-rc4 SMB Client /etc/krb5.keytab match_session weak password hash (Nessus ID 311783)
vuldb·2026-05-04·CVSS 8.1
CVE-2026-31392 [HIGH] Linux Kernel up to 7.0-rc4 SMB Client /etc/krb5.keytab match_session weak password hash (Nessus ID 311783)
A vulnerability, which was classified as critical, was found in Linux Kernel up to 7.0-rc4. Impacted is the function match_session of the file /etc/krb5.keytab of the component SMB Client. The manipulation results in password hash with insufficient computational effort.
This vulnerability is known as CVE-2026-31392. Access to the local network is required for this attack. No exploit is available.
You should upgrade the affected component.
GHSA
GHSA-h833-487p-56g8: In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix krb5 mount with username option
Customer reported that some of
ghsa_unreviewed·2026-04-03
CVE-2026-31392 GHSA-h833-487p-56g8: In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix krb5 mount with username option
Customer reported that some of
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.k
OSV
CVE-2026-31392: In the Linux kernel, the following vulnerability has been resolved: smb: client: fix krb5 mount with username option Customer reported that some of th
osv·2026-04-03
CVE-2026-31392 CVE-2026-31392: In the Linux kernel, the following vulnerability has been resolved: smb: client: fix krb5 mount with username option Customer reported that some of th
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.keyta
No detection rules found.
No public exploits indexed.
Wiz
CVE-2026-31392 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz
CVE-2026-31392 CVE-2026-31392 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-31392 :
Linux Kernel vulnerability analysis and mitigation
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 f
Bugzilla
CVE-2026-31392 kernel: smb: client: fix krb5 mount with username option
bugzilla·2026-04-03·CVSS 8.1
CVE-2026-31392 [HIGH] CVE-2026-31392 kernel: smb: client: fix krb5 mount with username option
CVE-2026-31392 kernel: smb: client: fix krb5 mount with username option
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 f
https://git.kernel.org/stable/c/12b4c5d98cd7ca46d5035a57bcd995df614c14e1https://git.kernel.org/stable/c/6e9ff1eb7feedcf46ff2d0503759960ab58e7775https://git.kernel.org/stable/c/9229709ec8bf85ae7ca53aeee9aa14814cdc1bd2https://git.kernel.org/stable/c/9ee803bfdba0cf739038dbdabdd4c02582c8f2b2https://git.kernel.org/stable/c/d33cbf0bf8979d779900da9be2505d68d9d8da25https://git.kernel.org/stable/c/fd4547830720647d4af02ee50f883c4b1cca06e4
2026-04-03
Published