# CVE-2020-8904: Arbitrary trusted memory overwrite vulnerability in Asylo

> Attackers can overwrite arbitrary trusted memory in Asylo enclaves due to missing pointer validation, potentially leading to code execution or privilege escalation.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:H`)
- **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:** 12 Aug 2020
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-pc43-829f-g5gr

## What is CVE-2020-8904?

CVE-2020-8904 is a medium-severity memory corruption vulnerability in Google LLC Asylo, published on 12 Aug 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An arbitrary memory overwrite vulnerability in the trusted memory of Asylo exists in versions prior to 0.6.0. As the ecall_restore function fails to validate the range of the output_len pointer, an attacker can manipulate the tmp_output_len value and write to an arbitrary location in the trusted (enclave) memory. We recommend updating Asylo to version 0.6.0 or later.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), CWE-823 (Use of Out-of-range Pointer Offset)

## Which versions are affected by CVE-2020-8904?

It affects 1 product.


Products: Google Asylo.

## How do I fix CVE-2020-8904?

No fix has been published for CVE-2020-8904 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-8904 being exploited?

There is no known exploitation of CVE-2020-8904 in the wild and no public exploit code.

## Other vulnerabilities in Google LLC Asylo

- [CVE-2021-22548](https://insights.sbomify.com/CVE-2021-22548/): Arbitrary enclave memory overread vulnerability in Asylo TrustedPrimitives::UntrustedCall (medium 6.5)
- [CVE-2021-22549](https://insights.sbomify.com/CVE-2021-22549/): Arbitrary enclave memory overwrite vulnerability in Asylo TrustedPrimitives::UntrustedCall (medium 6.5)
- [CVE-2021-22550](https://insights.sbomify.com/CVE-2021-22550/): Enclave memory overwrite/overread vulnerability in Asylo UntrustedCacheMalloc::GetBuffer (medium 6.5)
- [CVE-2021-22552](https://insights.sbomify.com/CVE-2021-22552/): Memory overread secure enclave in Asylo 0.6.2 (medium 5.3)
- [CVE-2020-8935](https://insights.sbomify.com/CVE-2020-8935/): Memory corruption in Asylo (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8904 and fix it if it is affected.

What it is: CVE-2020-8904 is a medium-severity memory corruption vulnerability in Google LLC Asylo, published on 12 Aug 2020. 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-2020-8904 in the wild and no public exploit code.

Affected product: Google LLC Asylo. 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-2020-8904/ (Markdown: https://insights.sbomify.com/CVE-2020-8904/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8904
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8904
- OSV: https://osv.dev/vulnerability/CVE-2020-8904

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8904/
Summaries are generated and may contain mistakes; the official description above is the record.