CVE-2026-42546 OP-TEE has missing OPTEE_MSG_ATTR_TYPE_MASK in cleanup_shm_refs() leaks mobj references

What is CVE-2026-42546?

CVE-2026-42546 is a low-severity denial of service vulnerability in OP-TEE optee_os, published on 6 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 3.3.0 and prior to version 4.11.0, a resource leak exists in OP-TEE’s shared memory cleanup logic because the function `cleanup_shm_refs()` in `core/tee/entry_std.c` fails to apply a required bitmask (`OPTEE_MSG_ATTR_TYPE_MASK`) to parameter attributes. When processing non-contiguous memory parameters from a normal-world caller, the system fails to match the attribute type in its internal switch statement and skips the necessary mobj_put() call. This results in a persistent reference leak of `mobj_reg_shm` objects, which remain on internal lists with dangling refcounts. This affects non-FF-A configurations that support non-contiguous, non-secure shared memory. Over time, these accumulated leaks progressively consume the secure-world heap, degrading the system's ability to service trusted application operations and eventually requiring a reboot to recover. Version 4.11.0 contains a patch. No known workarounds are available.

Weakness: CWE-770

Which versions are affected by CVE-2026-42546?

It affects 1 product.

Products include Trustedfirmware Op-Tee.

How do I fix CVE-2026-42546?

No fix has been published for CVE-2026-42546 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-42546 being exploited?

There is no known exploitation of CVE-2026-42546 in the wild and no public exploit code.

Other vulnerabilities in OP-TEE optee_os

• CVE-2019-1010292 Memory corruption in OP-TEE Critical 9.8
• CVE-2019-1010293 Memory corruption in OP-TEE Critical 9.8
• CVE-2019-1010295 Linaro/OP-TEE OP-TEE 3.3.0 and earlier is affected by: Buffer Overflow. Critical 9.8
• CVE-2019-1010296 Memory corruption in OP-TEE Critical 9.8
• CVE-2019-1010297 Memory corruption in OP-TEE Critical 9.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-42546, GHSA-c7j8-fgqw-rcgp, UBUNTU-CVE-2026-42546.