CVE-2026-46283
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
In the Linux kernel TPM driver, a vulnerability was found where tpm_dev_release() uses plain kfree() instead of kfree_sensitive() to free the auth session structure. This leaves sensitive cryptographic material such as HMAC session keys, nonces, and passphrase data in non-zeroed memory.
Risk Assessment
The risk involves potential leakage of confidential cryptographic material from kernel memory, which could allow an attacker with local access to recover TPM session keys and compromise trusted computing operations.
Recommendation
Immediately update the Linux kernel to a version containing the fix that uses kfree_sensitive() in tpm_dev_release(). Monitor official security advisories from your Linux distribution for the patch.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: tpm: Use kfree_sensitive() to free auth session in tpm_dev_release() tpm_dev_release() uses plain kfree() to free chip->auth, which contains sensitive cryptographic material including HMAC session keys, nonces, and passphrase data (struct tpm2_auth). Every other code path that frees this structure uses kfree_sensitive() to zero the memory before releasing it: both tpm2_end_auth_session() and tpm_buf_check_hmac_response() do so. The tpm_dev_release() path is the only one that does not, leaving key material in freed slab memory until it is eventually overwritten. Use kfree_sensitive() for consistency with the rest of the driver and to ensure session keys are scrubbed during device teardown.