UBUNTU-CVE-2026-99024: Medium severity ubuntu/linux-azure vulnerability
In the Linux kernel, the following vulnerability has been resolved: optee: register TEE devices only once fully initialized opteeprobe() called teedeviceregister() on both the client and the supplicant device before the rest of struct optee had been initialized. teedeviceregister() calls cdevdeviceadd(), which does two things at once: it creates /dev/tee0 and /dev/teepriv0, and it links the device into the tee class so that classfinddevice() can find it. From that moment on the device is reachable both from user space via teeopen() and from kernel space via teeclientopencontext(). The only gate in teedevopen() is teedeviceget(), which merely checks that teedev->desc is non-NULL, which was already set by teedevicealloc(). Therefore, there is effectively no gate at all. A context opened in that window can run against a struct optee where - optee->callqueue.mutex is not initialized by opteecqinit() - optee->supp mutex and completions is not initialized by opteesuppinit() - optee->rpmbdevmutex is not initialized yet, - the message argument cache is not initialized by opteeshmargcacheinit() - optee->ctx is still NULL Any open session or invoke during this window takes uninitialized mutexes and dereferences a NULL pointer. Fix it by moving both teedeviceregister() calls down to the point where all of struct optee is set up. [JW: adding fixes and cc]
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-aws-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1069.74~22.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1073.82~22.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-fde-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1071.78~22.04.1 - Upgrade
Upgrade
ubuntu/linux-gcp-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1073.81~22.04.1 - Upgrade
Upgrade
ubuntu/linux-ibm-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1069.70~22.04.1 - Upgrade
Upgrade
ubuntu/linux-lowlatency-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-149.149.1~22.04.1 - Upgrade
Upgrade
ubuntu/linux-oracle-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1067.71~22.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-149.149~22.04.2 - Upgrade
Upgrade
ubuntu/linux-realtime-6.8to a version that resolves this vulnerability.Fixed in 6.8.1-1064.65~22.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-149.149 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.8.0-1069.74 - Upgrade
Upgrade
ubuntu/linux-aws-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.18~24.04.1 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1073.82 - Upgrade
Upgrade
ubuntu/linux-azure-fde-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1019.19~24.04.1 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1073.81 - Upgrade
Upgrade
ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.19~24.04.1 - Upgrade
Upgrade
ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 6.8.0-1068.77 - Upgrade
Upgrade
ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 6.8.0-1053.57 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 6.8.0-1069.70 - Upgrade
Upgrade
ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-149.149.1 - Upgrade
Upgrade
ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1067.70 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1067.71 - Upgrade
Upgrade
ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1016.18~24.04.1 - Upgrade
Upgrade
ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 6.8.0-1068.72 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-43.43.1~24.04.2 - Upgrade
Upgrade
ubuntu/linux-vmwareto a version that resolves this vulnerability.Fixed in 6.8.0-1010.10 - Upgrade
Upgrade
ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 6.8.0-1036.41 - Upgrade
Upgrade
ubuntu/linux-raspi-realtimeto a version that resolves this vulnerability.Fixed in 6.8.0-2056.58 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.8.1-1064.65 - Upgrade
Upgrade
ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1069.74+fips1 - Upgrade
Upgrade
ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1073.82+fips1 - Upgrade
Upgrade
ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1073.81+fips1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.3.0-10.10 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.3.0-1004.4 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.3.0-1004.4 - Upgrade
Upgrade
ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.3.0-1004.5 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.3.0-1004.4 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.3.0-1004.4 - Upgrade
Upgrade
ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 7.3.0-1004.4 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.3.0-10.10.1 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.3.0-10.10.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-43.43 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1017.18 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1020.21 - Upgrade
Upgrade
ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1019.19 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1017.19 - Upgrade
Upgrade
ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 7.0.0-1010.11 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1018.18 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1018.18 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.0.0-43.43.1 - Compensating control
In optee_probe(), move both tee_device_register() calls until after all struct optee initialization is complete, including optee_cq_init(), optee_supp_init(), initialization of optee->rpmb_dev_mutex, optee_shm_arg_cache_init(), and assignment of optee->ctx.
Event History
Frequently Asked Questions
Who can reach the affected initialization window?
A user-space process that can open /dev/tee0 or /dev/teepriv0 can reach the device after it is registered but before OP-TEE initialization has completed. Kernel code can also reach it through tee_client_open_context().
What must happen for the issue to be triggered?
A context must be opened during the brief interval after device registration and before the OP-TEE structure is fully initialized, followed by an open session or invoke operation. During that window, synchronization primitives, shared-memory argument cache state, and the OP-TEE context may not yet be initialized.