Cloudanix VulnDB

CVE-2026-98845

None

CVSS

—

EPSS

0.2%

Published

Oct 18, 2026

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A Linux security-hardware check that should shut down a possibly tampered device instead lets it keep working, which could weaken protections on affected machines.

Chainable
Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Privilege Gain
Component
OS kernel
Class
Improper Input Validation
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

The null key name integrity check in tpm2_load_null fails to set an error code on mismatch, allowing the TPM chip to remain enabled and returning success with an unpopulated handle; callers then use uninitialized stack values as the salt key handle in operations such as tpm2_start_auth_session.

Why it matters to the business

Linux systems depending on TPM-protected operations face a risk that integrity failures are ignored, potentially undermining hardware-rooted security controls with low immediate urgency given the recent disclosure and low exploit probability.

How an attack unfolds

An attacker forces a TPM2_CC_CONTEXT_LOAD failure that triggers an integrity error, recreates the null key with a mismatched name, and observes that the chip continues accepting commands instead of disabling; the subsequent auth-session creation then proceeds with an invalid handle derived from the stack.

How to fix it

Apply the upstream kernel patch that sets rc to -ENODEV inside tpm2_load_null on null-key name mismatch so the error path disables the chip and returns the correct status to callers.

How to confirm the fix worked

Reproduce the integrity failure scenario in a test environment (QEMU + swtpm with CONFIG_TCG_TPM2_HMAC) and confirm the chip is disabled and the caller receives a non-zero return code.

Typical attack path

  1. Trigger a context-load operation that returns TPM2_RC_INTEGRITY
  2. Force recreation of the null key with altered name
  3. Observe continued TPM command processing after the logged mismatch
  4. Supply the uninitialized handle to tpm2_start_auth_session or similar calls

How to detect it

Search kernel logs and audit trails for the exact mismatch message and any subsequent TPM command activity that occurs after it; correlate with processes invoking tpm2_* functions.

  • tpm tpm0: null key integrity check failed
  • tpm2_load_null returning success despite integrity failure

What your security team should do

  • Monitor kernel logs for "tpm tpm0: null key integrity check failed"
  • Schedule kernel updates that include the -ENODEV fix
  • Verify TPM functionality after patching in representative test systems

The record

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 packages

Ecosystem Package Introduced Fixed