CVE-2026-52981: neigh: let neigh_xmit take skb ownership

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-24 · updated 2026-10-19
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: neigh: let neigh_xmit take skb ownership neigh_xmit always releases the skb, except when no neighbour table is found. But even the first added user of neigh_xmit (mpls) relied on neigh_xmit to release the skb (or queue it for tx). sashiko reported: If neigh_xmit() is called with an uninitialized neighbor table (for example, NEIGH_ND_TABLE when IPv6 is disabled), it returns -EAFNOSUPPORT and bypasses its internal out_kfree_skb error path. Because the return value of neigh_xmit() is ignored here, does this leak the SKB? Assume full ownership and remove the last code path that doesn't xmit or free skb.

Affected products

Linux kernel: from 4.1 before 6.1.175; from 6.2 before 6.6.141; from 6.7 before 6.12.91; from 6.13 before 6.18.33; from 6.19 before 7.0.10; 7.1-rc1 — fixed in 6.1.175, 6.12.91, 6.18.33, 6.6.141, 7.0.10

How to fix

Upgrade to a fixed version: Linux kernel 6.1.175, 6.12.91, 6.18.33, 6.6.141. Check the vendor advisory for mitigations.

References

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