CVE-2026-98845
In the Linux kernel, the following vulnerability has been resolved:
tpm: Disable TPM on null key name mismatch
The null key name check exists to protect against TPM reset attacks, so a mismatch should stop the device from serving further requests. Currently it does not disable the chip when it finds a mismatch.
The mismatch is logged:
but the chip keeps serving commands:
tpm2_load_null() where the null key name check is run sets the chip as disabled only if the rc is non zero. When the mismatch is seen, rc is zero at that point and it returns success. The other issue is that the caller expects the null key handle to be populated when the function returns 0 which it does here without writing the handle and proceeds assuming the null key handle is valid.
Read full descriptionShow less
During the test, I noticed that tpm2_start_auth_session() uses the uninitialized stack value as the key handle since tpm2_load_null() returns 0 despite the integrity failure and proceeds with TPM2_CC_START_AUTH_SESS with this value as salt key handle.
Set rc to -ENODEV on the mismatch. The error path then disables the chip and returns the correct code to the caller.
Tested in QEMU with swtpm and CONFIG_TCG_TPM2_HMAC=y by making TPM2_CC_CONTEXT_LOAD fail with TPM2_RC_INTEGRITY and changing the name of the re-created null key. The chip is now disabled on the mismatch.
Technical details traces, logs and code from the original report
tpm tpm0: null key integrity check failed
/ # tpm2_getcap -c properties-fixed
TPM_PT_FAMILY_INDICATOR:
as UINT32: 0x08322e3000
as string: "2.0"
...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
- 0.16 %
- Percentile among all scored CVEs
- 4
- 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)
Show
{
"id": "CVE-2026-98845",
"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": "cc7d8594342a25693d40fe96f97e5c6c29ee609c",
"lessThan": "a03d0c64cd827a622578623a78defd66b6593b82",
"versionType": "git"
},
{
"status": "affected",
"version": "cc7d8594342a25693d40fe96f97e5c6c29ee609c",
"lessThan": "96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa",
"versionType": "git"
},
{
"status": "affected",
"version": "cc7d8594342a25693d40fe96f97e5c6c29ee609c",
"lessThan": "f6599d8830fe7ddab7334cc17846fd9ac9a7fa50",
"versionType": "git"
},
{
"status": "affected",
"version": "cc7d8594342a25693d40fe96f97e5c6c29ee609c",
"lessThan": "015fb29a748342a186f37b602ac70017098c8251",
"versionType": "git"
},
{
"status": "affected",
"version": "294984ce51c19c2af3d0d71e1c8bd589bc86b8e2",
"versionType": "git"
},
{
"status": "affected",
"version": "386c7cc6c06d64cbf36d15c5e2319814765e107c",
"versionType": "git"
},
{
"status": "affected",
"version": "6.11.7",
"lessThan": "6.12",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.11.10",
"lessThan": "6.12",
"versionType": "semver"
}
],
"programFiles": [
"drivers/char/tpm/tpm2-sessions.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.12"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.12",
"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": [
"drivers/char/tpm/tpm2-sessions.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:38.833",
"references": [
{
"url": "https://git.kernel.org/stable/c/015fb29a748342a186f37b602ac70017098c8251",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a03d0c64cd827a622578623a78defd66b6593b82",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f6599d8830fe7ddab7334cc17846fd9ac9a7fa50",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntpm: Disable TPM on null key name mismatch\n\nThe null key name check exists to protect against TPM reset attacks, so\na mismatch should stop the device from serving further requests.\nCurrently it does not disable the chip when it finds a mismatch.\n\nThe mismatch is logged:\n\n tpm tpm0: null key integrity check failed\n\nbut the chip keeps serving commands:\n\n / # tpm2_getcap -c properties-fixed\n TPM_PT_FAMILY_INDICATOR:\n as UINT32: 0x08322e3000\n as string: \"2.0\"\n ...\n\ntpm2_load_null() where the null key name check is run sets the chip as\ndisabled only if the rc is non zero. When the mismatch is seen, rc is\nzero at that point and it returns success. The other issue is that the\ncaller expects the null key handle to be populated when the function\nreturns 0 which it does here without writing the handle and proceeds\nassuming the null key handle is valid.\n\nDuring the test, I noticed that tpm2_start_auth_session() uses the\nuninitialized stack value as the key handle since tpm2_load_null()\nreturns 0 despite the integrity failure and proceeds with\nTPM2_CC_START_AUTH_SESS with this value as salt key handle.\n\nSet rc to -ENODEV on the mismatch. The error path then disables the chip\nand returns the correct code to the caller.\n\nTested in QEMU with swtpm and CONFIG_TCG_TPM2_HMAC=y by making\nTPM2_CC_CONTEXT_LOAD fail with TPM2_RC_INTEGRITY and changing the name\nof the re-created null key. The chip is now disabled on the mismatch."
}
],
"lastModified": "2026-10-19T10:19:48.590",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}