CVE-2026-90110

/// Technical description

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

inetpeer: randomize RB-tree node comparison using SipHash

The inetpeer rate limiting system stores peer entries in a Red-Black tree

keyed deterministically on the remote IP address. Because tree lookups walk

the RB-tree using standard lexicographical comparisons (inetpeer_addr_cmp),

an off-path adversary can predict the exact topology of the tree and the

sequence of nodes traversed during lookups (the gc_stack candidate list).

By combining deterministic tree traversal with aggressive garbage collection

(triggered when tree size exceeds inet_peer_threshold), an attacker can

selectively force the eviction of targeted inet_peer nodes. When an evicted

node is subsequently re-created upon receiving a new packet, its rate-limiting

token bucket (rate_tokens, rate_last) is reset to full capacity. This creates

a side-channel primitive allowing off-path attackers to bypass IP-keyed ICMP

rate limits and infer open UDP ports (s

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References