CVE-2026-98805

/// Technical description

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

tipc: prevent GCM nonce reuse on peer key changes

TIPC can encrypt traffic between nodes using a different transmit key

for each node. In this mode, the AES-GCM nonce for a packet sent to a

known peer consists of a 32-bit prefix (a per-key salt XOR the peer's

address) followed by a 64-bit counter. That counter is stored in the

peer's RX crypto object. When the peer reports a change in which key

it uses to receive packets, TIPC resets this counter. The sender can

still be using the same TX key and salt, so subsequent packets reuse

earlier nonces. This nonce reuse breaks confidentiality and exposes

GCM's authentication key. This makes forgeries trivial: an attacker

can exploit CTR malleability to alter captured ciphertexts and use the

recovered authentication key to compute a valid tag for the modified

ciphertext, under the same key and nonce.

Use the TX key's existing aead->seqno counter instead. All encryptions

usin

/// 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