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tipc: prevent GCM nonce reuse on peer key changes

Type: advisorySources: OSV

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 st

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.273, 5.15.224, 6.1.191, 6.12.113, 6.18.56, 6.6.160, 7.2.10
CVEs
CVE-2026-98805
Confirmed fixed CVEs
Not specified
Updated in this feed
5 Nov 2026, 00:01 UTC · Revision 1

Source evidence

tipc: prevent GCM nonce reuse on peer key changes

core-osv · Original source

Published 18 Oct 2026, 15:48 UTC

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 st

osv:CVE-2026-98805

Kernel

Fixed versions: 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10

Complete source record
{
  "id": "be5c3ac2002003da8ab6225473c27b0a305714731f5639f0243c82858002bd51",
  "url": "https://osv.dev/vulnerability/CVE-2026-98805",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tipc: prevent GCM nonce reuse on peer key changes",
    "summary": "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 st",
    "evidence": "osv:CVE-2026-98805",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.273",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.224",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.191",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.160",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.113",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.56",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98805",
      "aliases": [
        "CVE-2026-98805"
      ],
      "affected": [
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          "ranges": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "04d67f77fe3f9ec9c60db70773fb1696d0d58da8"
                },
                {
                  "fixed": "7e5d5ac25e0857548cac963a2f850b19b2e1d59c"
                },
                {
                  "fixed": "0ff0ca5b514ceecad68b8682e072f373acc5acec"
                },
                {
                  "fixed": "a85a3dce4b6c73ddaa1e9725b906249744bf7cf2"
                },
                {
                  "fixed": "5c8ce13c792e28d56f9ec3cd6728d8225bc0e3a2"
                },
                {
                  "fixed": "f74f100e49588c1dbdc6ab3ba9e2c67b36d015d0"
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                {
                  "fixed": "60e0c2aeaa605ff19ca4e65126a35643d4d7ee1c"
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                  "fixed": "512ccd3d0e91e791fb37442aa0a2599aca19783d"
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          ],
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          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.5.0"
                },
                {
                  "fixed": "5.10.273"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.224"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.191"
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              ]
            },
            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.2.0"
                },
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                  "introduced": "6.7.0"
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            },
            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.13.0"
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                {
                  "fixed": "6.18.56"
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            },
            {
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                  "introduced": "6.19.0"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98805.json"
          }
        }
      ],
      "modified": "2026-11-01T02:30:28.310985752Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/04d67f77fe3f9ec9c60db70773fb1696d0d58da8",
        "https://git.kernel.org/stable/c/0ff0ca5b514ceecad68b8682e072f373acc5acec",
        "https://git.kernel.org/stable/c/512ccd3d0e91e791fb37442aa0a2599aca19783d",
        "https://git.kernel.org/stable/c/5c8ce13c792e28d56f9ec3cd6728d8225bc0e3a2",
        "https://git.kernel.org/stable/c/60e0c2aeaa605ff19ca4e65126a35643d4d7ee1c",
        "https://git.kernel.org/stable/c/7e5d5ac25e0857548cac963a2f850b19b2e1d59c",
        "https://git.kernel.org/stable/c/a85a3dce4b6c73ddaa1e9725b906249744bf7cf2",
        "https://git.kernel.org/stable/c/f74f100e49588c1dbdc6ab3ba9e2c67b36d015d0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98805.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98805",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98805.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98805",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 508218,
  "published_at": "2026-10-18T15:48:51.902+00:00"
}