Unchecked Return Value in tpm2-tss - CVE-2026-73984
Published: November 4, 2026
Vulnerability identifier: #VU159292
CSH Severity: Low
CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-73984
CWE-ID: CWE-252
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass policy and attestation checks by causing malformed TPM data to be accepted as valid.
The vulnerability exists due to an unchecked return value in the TPM2B_UNMARSHAL_SUBTYPE macro in src/tss2-mu/tpm2b-types.c when decoding TPM2B subtype payloads. A remote attacker can supply a crafted TPM response with a valid outer size field and a malformed inner subtype to cause partially decoded structures to be accepted as valid, potentially bypassing downstream policy and attestation checks.
Affected software
tpm2-tss
How to mitigate CVE-2026-73984
Install security update from vendor's website.
tpm2-tss - addressed in versions 4.1.4, 4.2.0