CVE-2026-31392
8.1 · HIGHOverview
CVE-2026-31392 is a high-severity vulnerability affecting linux linux_kernel. It was published on April 3, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical 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 tes
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 2.6.32.44, < 2.6.33 | Affected |
References
Frequently Asked Questions
What is CVE-2026-31392?
CVE-2026-31392 is a high-severity vulnerability affecting linux linux_kernel. It was published on April 3, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).
How severe is CVE-2026-31392?
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-31392?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-31392?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-31392 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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