CVE-2026-72151: tpm: tpm2-sessions: wait for async KPP completion in tpm_buf_append_salt
In the Linux kernel, the following vulnerability has been resolved:
tpm: tpm2-sessions: wait for async KPP completion in tpmbufappendsalt
tpmbufappendsalt() in drivers/char/tpm/tpm2-sessions.c calls cryptokppgeneratepublickey() and cryptokppcomputesharedsecret() without installing a completion callback, discards both return values, and immediately frees the kpprequest via kpprequestfree(). When the resolved ecdh-nist-p256 KPP backend is asynchronous (atmel-ecc, HPRE, keembay-ocs), either operation returns -EINPROGRESS and the deferred completion worker dereferences the freed request.
The path fires automatically from the hwrngfillfn kernel thread via tpmgetrandom -> tpm2getrandom -> tpm2startauthsession -> tpmbufappendsalt on every entropy poll, without any userland action.
Install cryptoreqdone as the completion callback, wrap both KPP operations in cryptowaitreq(), and propagate errors to the caller. The wait is a no-op for synchronous backends.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-aws-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17~24.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-fde-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1016.16~24.04.1 - Upgrade
Upgrade
ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38~24.04.4 - Upgrade
Upgrade
ubuntu/linux-nvidia-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1024.25~24.04.1 - Upgrade
Upgrade
ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-38.38 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1016.16 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
Upgrade
ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 7.0.0-1008.9 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
Upgrade
ubuntu/linux-nvidia-bosto a version that resolves this vulnerability.Fixed in 7.0.0-2022.23 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72151?
The severity of CVE-2026-72151 is rated at 75, indicating it is a significant risk.
How do I fix CVE-2026-72151?
To fix CVE-2026-72151, update to the latest version of the Linux kernel that addresses this vulnerability.
What systems are affected by CVE-2026-72151?
CVE-2026-72151 affects Linux systems using the TPM2 sessions functionality in their kernel.
What type of vulnerability is CVE-2026-72151?
CVE-2026-72151 is a vulnerability related to the improper handling of asynchronous Key Pair Processing in the Linux kernel.
When was CVE-2026-72151 published?
CVE-2026-72151 was published on August 15, 2026.