What’s Vulnerable › Vulnerabilities

CVE-2026-80586: mptcp: options: reset DSS fields in case of unexpected size

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-26 · updated 2026-10-16

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: options: reset DSS fields in case of unexpected size A remote peer could send a malformed DSS with a wrong size, followed by another DSS or MPC + Data. In this case, the first suboption will be ignored, but leaving some fields written, which could lead to inconsistency or access uninitialized data. Explicitly reset the fields that could have been modified in case of unexpected size.

Affected products

• Linux kernel: 5.6 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/15e35fdad7a5576bf3f1c8d688877aeb5d1b506b
• https://git.kernel.org/stable/c/192878df582c51d440bf7b91a15f297f29f2b596
• https://git.kernel.org/stable/c/1fade1b2ac5b1a4948e538fae7313bea57b5ac36
• https://git.kernel.org/stable/c/26dac5c9ffb20812b475fdf253eb04fab99cff3b
• https://git.kernel.org/stable/c/27ed642a4e7e4b5df4b8522c72c457a67e052493
• https://git.kernel.org/stable/c/35772b4981f38ba8059372cde8753e8e477e98ec
• https://git.kernel.org/stable/c/4e80eff5c1c893aca2ac1d202f0b256d2e52ecde
• https://git.kernel.org/stable/c/b1256090816ec46011601e084be580731df58fc7

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