CVE-2026-46283: tpm: Use kfree_sensitive() to free auth session in tpm_dev_release()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-08 · updated 2026-07-23

Description

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.

Affected products

Linux kernel: from 6.10 before 6.12.86; from 6.13 before 6.18.27; from 6.19 before 7.0.4 — fixed in 6.12.86, 6.18.27, 7.0.4

How to fix

Upgrade to a fixed version: Linux kernel 6.12.86, 6.18.27, 7.0.4. Check the vendor advisory for mitigations.

References

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