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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-98805

tipc: prevent GCM nonce reuse on peer key changes

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Status
Published
Published
Updated
Assigning organization
Linux

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 using that key object share the same atomic counter, so concurrent encryptions get distinct nonce counter values. The counter survives key activation and peer reconnection, and peer key-status reports cannot reset it. This prevents those transitions from causing nonce reuse while the same TX key remains installed. The nonce format is unchanged, and receivers do not require consecutive counter values, so sharing the counter across peers remains compatible with existing receivers. A pre-existing check still invokes key revocation in the unlikely event that the counter wraps to zero.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 to < a85a3dce4b6c73ddaa1e9725b906249744bf7cf2affected
  • fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 to < 5c8ce13c792e28d56f9ec3cd6728d8225bc0e3a2affected
  • fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 to < f74f100e49588c1dbdc6ab3ba9e2c67b36d015d0affected
  • fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 to < 60e0c2aeaa605ff19ca4e65126a35643d4d7ee1caffected
  • fc1b6d6de2208774efd2a20bf0daddb02d18b1e0 to < 512ccd3d0e91e791fb37442aa0a2599aca19783daffected

Linux Linux

Default version status: affected

  • 5.5affected
  • 0 to < 5.5unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.113 to ≤ 6.12.*unaffected
  • 6.18.56 to ≤ 6.18.*unaffected
  • 7.2.10 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References