CVE-2026-23048: udp: call skb_orphan() before skb_attempt_defer_free()

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-04 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: udp: call skb_orphan() before skb_attempt_defer_free() Standard UDP receive path does not use skb->destructor. But skmsg layer does use it, since it calls skb_set_owner_sk_safe() from udp_read_skb(). This then triggers this warning in skb_attempt_defer_free(): DEBUG_NET_WARN_ON_ONCE(skb->destructor); We must call skb_orphan() to fix this issue.

Affected products

Linux kernel: 6.18 — fixed in 6.19

How to fix

Upgrade to a fixed version: Linux kernel 6.19. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/0c63d5683eae6a7b4d81382bcbecb2a19feff90d
https://git.kernel.org/stable/c/e5c8eda39a9fc1547d1398d707aa06c1d080abdd

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