{"id":"CVE-2026-98845","title":"tpm: Disable TPM on null key name mismatch","summary":"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 furth…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= cc7d8594342a25693d40fe96f97e5c6c29ee609c < a03d0c64cd827a622578623a78defd66b6593b82","Linux >= cc7d8594342a25693d40fe96f97e5c6c29ee609c < 96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa","Linux >= cc7d8594342a25693d40fe96f97e5c6c29ee609c < f6599d8830fe7ddab7334cc17846fd9ac9a7fa50","Linux >= cc7d8594342a25693d40fe96f97e5c6c29ee609c < 015fb29a748342a186f37b602ac70017098c8251","Linux 294984ce51c19c2af3d0d71e1c8bd589bc86b8e2","Linux 386c7cc6c06d64cbf36d15c5e2319814765e107c","Linux >= 6.11.7 < 6.12","Linux >= 6.11.10 < 6.12","Linux 6.12"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:50:27.596Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98845","references":[{"url":"https://git.kernel.org/stable/c/a03d0c64cd827a622578623a78defd66b6593b82"},{"url":"https://git.kernel.org/stable/c/96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa"},{"url":"https://git.kernel.org/stable/c/f6599d8830fe7ddab7334cc17846fd9ac9a7fa50"},{"url":"https://git.kernel.org/stable/c/015fb29a748342a186f37b602ac70017098c8251"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T16:47:32.466Z","slug":"CVE-2026-98845","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= cc7d8594342a25693d40fe96f97e5c6c29ee609c < a03d0c64cd827a622578623a78defd66b6593b82`\n- `Linux >= cc7d8594342a25693d40fe96f97e5c6c29ee609c < 96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa`\n- `Linux >= cc7d8594342a25693d40fe96f97e5c6c29ee609c < f6599d8830fe7ddab7334cc17846fd9ac9a7fa50`\n- `Linux >= cc7d8594342a25693d40fe96f97e5c6c29ee609c < 015fb29a748342a186f37b602ac70017098c8251`\n- `Linux 294984ce51c19c2af3d0d71e1c8bd589bc86b8e2`\n- `Linux 386c7cc6c06d64cbf36d15c5e2319814765e107c`\n- `Linux >= 6.11.7 < 6.12`\n- `Linux >= 6.11.10 < 6.12`\n- `Linux 6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}