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

> Attackers can exhaust secure-world heap memory via resource leaks in OP-TEE, causing denial of service requiring a reboot.

- **Severity:** Low 3.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Jul 2026
- **Updated:** 6 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-42546, GHSA-c7j8-fgqw-rcgp, UBUNTU-CVE-2026-42546

## 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 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-42546?

It affects 1 product.


Products: 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.

## 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](https://insights.sbomify.com/CVE-2019-1010292/): Memory corruption in OP-TEE (critical 9.8)
- [CVE-2019-1010293](https://insights.sbomify.com/CVE-2019-1010293/): Memory corruption in OP-TEE (critical 9.8)
- [CVE-2019-1010295](https://insights.sbomify.com/CVE-2019-1010295/): Linaro/OP-TEE OP-TEE 3.3.0 and earlier is affected by: Buffer Overflow. (critical 9.8)
- [CVE-2019-1010296](https://insights.sbomify.com/CVE-2019-1010296/): Memory corruption in OP-TEE (critical 9.8)
- [CVE-2019-1010297](https://insights.sbomify.com/CVE-2019-1010297/): Memory corruption in OP-TEE (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42546 and fix it if it is affected.

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

Affected product: OP-TEE optee_os. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42546/ (Markdown: https://insights.sbomify.com/CVE-2026-42546/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42546
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42546
- OSV: https://osv.dev/vulnerability/CVE-2026-42546

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-42546/
Summaries are generated and may contain mistakes; the official description above is the record.