CVE-2026-43093: xsk: tighten UMEM headroom validation to account for tailroom and min frame

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-06 · updated 2026-10-19
Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: xsk: tighten UMEM headroom validation to account for tailroom and min frame The current headroom validation in xdp_umem_reg() could leave us with insufficient space dedicated to even receive minimum-sized ethernet frame. Furthermore if multi-buffer would come to play then skb_shared_info stored at the end of XSK frame would be corrupted. HW typically works with 128-aligned sizes so let us provide this value as bare minimum. Multi-buffer setting is known later in the configuration process so besides accounting for 128 bytes, let us also take care of tailroom space upfront.

Affected products

Linux kernel: from 4.19.118 before 4.20; from 5.4.35 before 5.5; from 5.6.7 before 5.7; from 5.7.1 before 6.6.136; from 6.7 before 6.12.83; from 6.13 before 6.18.24 — fixed in 4.20, 5.5, 5.7, 6.12.83, 6.18.24, 6.19.14

How to fix

Upgrade to a fixed version: Linux kernel 4.20, 5.5, 5.7, 6.12.83. Check the vendor advisory for mitigations.

References

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