CVE-2026-98805
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.
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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.
CVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.13 %
- Percentile among all scored CVEs
- 3
- Score date
- 10/20/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Show 4 references
Raw JSON (NVD)
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{
"id": "CVE-2026-98805",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "fc1b6d6de2208774efd2a20bf0daddb02d18b1e0",
"lessThan": "5c8ce13c792e28d56f9ec3cd6728d8225bc0e3a2",
"versionType": "git"
},
{
"status": "affected",
"version": "fc1b6d6de2208774efd2a20bf0daddb02d18b1e0",
"lessThan": "f74f100e49588c1dbdc6ab3ba9e2c67b36d015d0",
"versionType": "git"
},
{
"status": "affected",
"version": "fc1b6d6de2208774efd2a20bf0daddb02d18b1e0",
"lessThan": "60e0c2aeaa605ff19ca4e65126a35643d4d7ee1c",
"versionType": "git"
},
{
"status": "affected",
"version": "fc1b6d6de2208774efd2a20bf0daddb02d18b1e0",
"lessThan": "512ccd3d0e91e791fb37442aa0a2599aca19783d",
"versionType": "git"
}
],
"programFiles": [
"net/tipc/crypto.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.5"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.5",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.113",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.56",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.10",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/tipc/crypto.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:34.567",
"references": [
{
"url": "https://git.kernel.org/stable/c/512ccd3d0e91e791fb37442aa0a2599aca19783d",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/5c8ce13c792e28d56f9ec3cd6728d8225bc0e3a2",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/60e0c2aeaa605ff19ca4e65126a35643d4d7ee1c",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f74f100e49588c1dbdc6ab3ba9e2c67b36d015d0",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: prevent GCM nonce reuse on peer key changes\n\nTIPC can encrypt traffic between nodes using a different transmit key\nfor each node. In this mode, the AES-GCM nonce for a packet sent to a\nknown peer consists of a 32-bit prefix (a per-key salt XOR the peer's\naddress) followed by a 64-bit counter. That counter is stored in the\npeer's RX crypto object. When the peer reports a change in which key\nit uses to receive packets, TIPC resets this counter. The sender can\nstill be using the same TX key and salt, so subsequent packets reuse\nearlier nonces. This nonce reuse breaks confidentiality and exposes\nGCM's authentication key. This makes forgeries trivial: an attacker\ncan exploit CTR malleability to alter captured ciphertexts and use the\nrecovered authentication key to compute a valid tag for the modified\nciphertext, under the same key and nonce.\n\nUse the TX key's existing aead->seqno counter instead. All encryptions\nusing that key object share the same atomic counter, so concurrent\nencryptions get distinct nonce counter values. The counter survives\nkey activation and peer reconnection, and peer key-status reports\ncannot reset it. This prevents those transitions from causing nonce\nreuse while the same TX key remains installed.\n\nThe nonce format is unchanged, and receivers do not require consecutive\ncounter values, so sharing the counter across peers remains compatible\nwith existing receivers. A pre-existing check still invokes key\nrevocation in the unlikely event that the counter wraps to zero."
}
],
"lastModified": "2026-10-19T10:19:44.560",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}