# CVE-2020-12883: Memory corruption in n/a

> A buffer over-read in the Mbed OS CoAP parser allows attackers to read out-of-bounds memory, potentially causing crashes or information disclosure.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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-x723-g4p2-w8m5

## What is CVE-2020-12883?

CVE-2020-12883 is a critical memory corruption 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

Buffer over-reads were 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() parses CoAP input linearly using a while loop. Once an option is parsed in a loop, the current point (*packet_data_pptr) is increased correspondingly. The pointer is restricted by the size of the received buffer, as well as by the option delta and option length bytes. The actual input packet length is not verified against the number of bytes read when processing the option extended delta and the option extended length. Moreover, the calculation of the message_left variable, in the case of non-extended option deltas, is incorrect and indicates more data left for processing than provided in the function input. All of these lead to heap-based or stack-based memory location read access that is outside of the intended boundary of the buffer. Depending on the platform-specific memory management mechanisms, it can lead to processing of unintended inputs or system memory access violation errors.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2020-12883?

It affects 1 product.


Products: Arm Mbed Os.

## How do I fix CVE-2020-12883?

No fix has been published for CVE-2020-12883 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-12883 being exploited?

There is no known exploitation of CVE-2020-12883 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-2020-12884](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-2020-12885](https://insights.sbomify.com/CVE-2020-12885/): Denial of service in n/a (high 7.5)
- [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-2020-12883 and fix it if it is affected.

What it is: CVE-2020-12883 is a critical memory corruption 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-2020-12883 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-2020-12883/ (Markdown: https://insights.sbomify.com/CVE-2020-12883/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-12883
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-12883
- OSV: https://osv.dev/vulnerability/CVE-2020-12883

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-12883/
Summaries are generated and may contain mistakes; the official description above is the record.