CVE-2026-98845

tpm: Disable TPM on null key name mismatch

Published Oct 18, 2026 CVSS 3.1 · 4.5 Medium EPSS < 1% KEV · Not listed

Description

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:

tpm tpm0: null key integrity check failed

but the chip keeps serving commands:

/ # tpm2_getcap -c properties-fixed
TPM_PT_FAMILY_INDICATOR:
as UINT32: 0x08322e3000
as string: "2.0"
...

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.

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.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`cc7d8594342a25693d40fe96f97e5c6c29ee609c`	affected	< a03d0c64cd827a622578623a78defd66b6593b82
`cc7d8594342a25693d40fe96f97e5c6c29ee609c`	affected	< 96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa
`cc7d8594342a25693d40fe96f97e5c6c29ee609c`	affected	< f6599d8830fe7ddab7334cc17846fd9ac9a7fa50
`cc7d8594342a25693d40fe96f97e5c6c29ee609c`	affected	< 015fb29a748342a186f37b602ac70017098c8251
`294984ce51c19c2af3d0d71e1c8bd589bc86b8e2`	affected	—
`386c7cc6c06d64cbf36d15c5e2319814765e107c`	affected	—
`6.11.7`	affected	< 6.12
`6.11.10`	affected	< 6.12

Linux

affected

Version	Status	Constraints
`6.12`	affected	—
`0`	unaffected	< 6.12
`6.12.113`	unaffected	≤ 6.12.*
`6.18.56`	unaffected	≤ 6.18.*
`7.2.10`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Versions

Linux

Linux Kernel

Version	Status	Scheme	Platform
`[cc7d8594342a25693d40fe96f97e5c6c29ee609c,a03d0c64cd827a622578623a78defd66b6593b82)`	affected	code_commit	—
`[cc7d8594342a25693d40fe96f97e5c6c29ee609c,96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa)`	affected	code_commit	—
`[cc7d8594342a25693d40fe96f97e5c6c29ee609c,f6599d8830fe7ddab7334cc17846fd9ac9a7fa50)`	affected	code_commit	—
`[cc7d8594342a25693d40fe96f97e5c6c29ee609c,015fb29a748342a186f37b602ac70017098c8251)`	affected	code_commit	—
`294984ce51c19c2af3d0d71e1c8bd589bc86b8e2`	affected	code_commit	—
`386c7cc6c06d64cbf36d15c5e2319814765e107c`	affected	code_commit	—
`[6.11.7,6.12)`	affected	semver	—
`[6.11.10,6.12)`	affected	semver	—

Linux

Linux Kernel

Version	Status	Scheme	Platform
`6.12`	affected	generic	—
`[0,6.12)`	unaffected	generic	—
`[6.12.113,6.13.0)`	unaffected	semver	—
`[6.18.56,6.19.0)`	unaffected	semver	—
`[7.2.10,7.3.0)`	unaffected	semver	—
`[7.3,*]`	unaffected	generic	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
Debian DLA	DLA-4850-1	linux-6.12 security update
Ubuntu USN	USN-9018-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9018-2	Linux kernel (HWE) vulnerabilities
Ubuntu USN	USN-9019-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9020-1	Linux kernel vulnerabilities

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.156% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98845.mbox
https://git.kernel.org/stable/c/015fb29a748342a186f37b602ac70017098c8251
https://git.kernel.org/stable/c/96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa
https://git.kernel.org/stable/c/a03d0c64cd827a622578623a78defd66b6593b82
https://git.kernel.org/stable/c/f6599d8830fe7ddab7334cc17846fd9ac9a7fa50
https://nvd.nist.gov/vuln/detail/CVE-2026-98845
https://www.cve.org/CVERecord?id=CVE-2026-98845

History

Oct 24, 2026 3:45 AM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses	CWE-640 CWE-693

Oct 24, 2026 12:30 AM Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-393
References		https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98845.mbox https://nvd.nist.gov/vuln/detail/CVE-2026-98845 https://www.cve.org/CVERecord?id=CVE-2026-98845
Metrics	threat_severity `None`	cvssV3_1 `{'score': 4.5, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L'}` threat_severity `Moderate`

Oct 18, 2026 10:15 PM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-640 CWE-693

Oct 18, 2026 4:00 PM Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references View changes

Type	Values Removed	Values Added
Description		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: tpm tpm0: null key integrity check failed but the chip keeps serving commands: / # tpm2_getcap -c properties-fixed TPM_PT_FAMILY_INDICATOR: as UINT32: 0x08322e3000 as string: "2.0" ... 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. 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.
Title		tpm: Disable TPM on null key name mismatch
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/015fb29a748342a186f37b602ac70017098c8251 https://git.kernel.org/stable/c/96c46c75b0d470b4204f9fe1bdb075cd2ebaebfa https://git.kernel.org/stable/c/a03d0c64cd827a622578623a78defd66b6593b82 https://git.kernel.org/stable/c/f6599d8830fe7ddab7334cc17846fd9ac9a7fa50