# CVE-2020-7766: Prototype Pollution

> Prototype pollution in json-ptr allows attackers to modify object prototypes when the force flag is enabled, potentially leading to code execution or privilege escalation.

- **Severity:** High 7.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Nov 2020
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-x5r6-x823-9848

## What is CVE-2020-7766?

CVE-2020-7766 is a high-severity vulnerability in json-ptr, published on 10 Nov 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

This affects all versions of package json-ptr. The issue occurs in the set operation (https://flitbit.github.io/json-ptr/classes/_src_pointer_.jsonpointer.htmlset) when the force flag is set to true. The function recursively set the property in the target object, however it does not properly check the key being set, leading to a prototype pollution.

Weakness: CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2020-7766?

2 open source packages ship an affected version, including json-ptr. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `json-ptr` | npm | All versions | 2.1.0 |
| `json-ptr` | npm | All versions | 2.1.0 |

Products: Json-Ptr Project Json-Ptr.

## How do I fix CVE-2020-7766?

Upgrade json-ptr to 2.1.0 or later.

## Is CVE-2020-7766 being exploited?

There is no known exploitation of CVE-2020-7766 in the wild and no public exploit code.

## Other vulnerabilities in json-ptr

- [CVE-2021-23509](https://insights.sbomify.com/CVE-2021-23509/): Prototype Pollution (medium 5.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-7766 and fix it if it is affected.

What it is: CVE-2020-7766 is a high-severity vulnerability in json-ptr, published on 10 Nov 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-2020-7766 in the wild and no public exploit code.

Affected packages and fixed versions:
- json-ptr (npm): affected all versions; fixed in 2.1.0
- json-ptr (npm): affected all versions; fixed in 2.1.0

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-2020-7766/ (Markdown: https://insights.sbomify.com/CVE-2020-7766/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-7766
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-7766
- OSV: https://osv.dev/vulnerability/CVE-2020-7766

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-7766/
Summaries are generated and may contain mistakes; the official description above is the record.