CVE-2026-23083: fou: Don't allow 0 for FOU_ATTR_IPPROTO.

Published Feb 4, 2026
·
Updated

In the Linux kernel, the following vulnerability has been resolved:

fou: Don't allow 0 for FOUATTRIPPROTO.

fouudprecv() has the same problem mentioned in the previous patch.

If FOUATTRIPPROTO is set to 0, skb is not freed by fouudprecv() nor "resubmit"-ted in ipprotocoldeliverrcu().

Let's forbid 0 for FOUATTRIPPROTO.

Affected Software

13 affected components
linux_kernel
Linux Linux kernel>=3.18<5.10.249
Linux Linux kernel>=5.11<5.15.199
Linux Linux kernel>=5.16<6.1.162
Linux Linux kernel>=6.2<6.6.122
Linux Linux kernel>=6.7<6.12.68
Linux Linux kernel>=6.13<6.18.8
Linux Linux kernel=6.19-rc1
Linux Linux kernel=6.19-rc2
Linux Linux kernel=6.19-rc3
Linux Linux kernel=6.19-rc4
Linux Linux kernel=6.19-rc5
Linux Linux kernel=6.19-rc6

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Configuration

    Update/fix the kernel so FOU_ATTR_IPPROTO=0 is not allowed ("Let's forbid 0 for FOU_ATTR_IPPROTO" / "fou: Don't allow 0 for FOU_ATTR_IPPROTO").

    Linux kernel (fou/fou_udp_recv) FOU_ATTR_IPPROTO = Forbid value 0

Event History

Feb 4, 2026
CVE Published
via MITRE·04:08 PM
Data Sourced
via MITRE·04:08 PM
Description
Data Sourced
via NVD·05:16 PM
RemedyDescriptionSeverityAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-23083?

CVE-2026-23083 is considered a moderate severity vulnerability because it can lead to resource leaks in the Linux kernel.

2

How do I fix CVE-2026-23083?

To fix CVE-2026-23083, update your Linux kernel to a version that is patched against this vulnerability.

3

Which versions of Linux kernel are affected by CVE-2026-23083?

CVE-2026-23083 affects various Linux kernel versions from 3.18 to 6.19-rc6.

4

What is the nature of the vulnerability CVE-2026-23083?

CVE-2026-23083 is a vulnerability that does not allow the FOU_ATTR_IPPROTO to be set to 0, potentially causing resource not being freed.

5

Does CVE-2026-23083 affect both production and development environments?

Yes, CVE-2026-23083 can affect both production and development environments using the vulnerable Linux kernel versions.

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