# CVE-2020-12887: Integer overflow in n/a

> An integer overflow in the CoAP parser allows attackers to cause memory leaks via crafted packets, potentially leading to denial of service in IoT devices.

- **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-p665-3xc8-4hrv

## What is CVE-2020-12887?

CVE-2020-12887 is a high-severity 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

Memory leaks were discovered in the CoAP library in Arm Mbed OS 5.15.3 when using the Arm mbed-coap library 5.1.5. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses the CoAP option number field of all options present in the input packet. Each option number is calculated as a sum of the previous option number and a delta of the current option. The delta and the previous option number are expressed as unsigned 16-bit integers. Due to lack of overflow detection, it is possible to craft a packet that wraps the option number around and results in the same option number being processed again in a single packet. Certain options allocate memory by calling a memory allocation function. In the cases of COAP_OPTION_URI_QUERY, COAP_OPTION_URI_PATH, COAP_OPTION_LOCATION_QUERY, and COAP_OPTION_ETAG, there is no check on whether memory has already been allocated, which in conjunction with the option number integer overflow may lead to multiple assignments of allocated memory to a single pointer. This has been demonstrated to lead to memory leak by buffer orphaning. As a result, the memory is never freed.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime), CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2020-12887?

It affects 1 product.


Products: Arm Mbed-Coap.

## How do I fix CVE-2020-12887?

No fix has been published for CVE-2020-12887 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-12887 being exploited?

There is no known exploitation of CVE-2020-12887 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-12887 and fix it if it is affected.

What it is: CVE-2020-12887 is a high-severity 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-2020-12887 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-2020-12887/ (Markdown: https://insights.sbomify.com/CVE-2020-12887/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-12887
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-12887
- OSV: https://osv.dev/vulnerability/CVE-2020-12887

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-12887/
Summaries are generated and may contain mistakes; the official description above is the record.