# CVE-2020-12885: Denial of service in n/a

> An attacker can cause a denial of service in Arm Mbed OS by sending a crafted CoAP packet that triggers an infinite loop in the parser.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Jun 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-jhjh-34gq-3m8c

## What is CVE-2020-12885?

CVE-2020-12885 is a high-severity denial of service vulnerability in n/a, published on 18 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An infinite loop was discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse_multiple_options() parses CoAP options in a while loop. This loop's exit condition is computed using the previously allocated heap memory required for storing the result of parsing multiple options. If the input heap memory calculation results in zero bytes, the loop exit condition is never met and the loop is not terminated. As a result, the packet parsing function never exits, leading to resource consumption.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2020-12885?

It affects 1 product.


Products: Arm Mbed Os.

## How do I fix CVE-2020-12885?

No fix has been published for CVE-2020-12885 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-12885 being exploited?

There is no known exploitation of CVE-2020-12885 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2024-48984](https://insights.sbomify.com/CVE-2024-48984/): Memory corruption in n/a (critical 9.8)
- [CVE-2020-12883](https://insights.sbomify.com/CVE-2020-12883/): Memory corruption in n/a (critical 9.1)
- [CVE-2020-12884](https://insights.sbomify.com/CVE-2020-12884/): Memory corruption in n/a (critical 9.1)
- [CVE-2020-12886](https://insights.sbomify.com/CVE-2020-12886/): Memory corruption in n/a (critical 9.1)
- [CVE-2024-22905](https://insights.sbomify.com/CVE-2024-22905/): Memory corruption in n/a (high 7.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-12885 and fix it if it is affected.

What it is: CVE-2020-12885 is a high-severity denial of service vulnerability in n/a, published on 18 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-12885 in the wild and no public exploit code.

Affected product: n/a. 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-2020-12885/ (Markdown: https://insights.sbomify.com/CVE-2020-12885/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-12885
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-12885
- OSV: https://osv.dev/vulnerability/CVE-2020-12885

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-12885/
Summaries are generated and may contain mistakes; the official description above is the record.