# CVE-2021-31684: Out of bounds read in json-smart

> Attackers can cause a denial of service in applications using JSON Smart by sending crafted web requests that trigger an out-of-bounds write.

- **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:** Yes
- **Published:** 1 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** CLEANSTART-2026-FO78987, CLEANSTART-2026-GB22495, CLSA-2026-1773015250, CLSA-2026-1789372281, CLSA-2026-1789461880, DEBIAN-CVE-2021-31684, ECHO-5abf-ee02-406a, GHSA-fg2v-w576-w4v3, MINI-jmm2-mfmr-6wm3, MINI-qhh6-p4hr-x8pp, MINI-vxm4-m6hj-qvj5, MINI-w272-p543-x4cp, UBUNTU-CVE-2021-31684

## What is CVE-2021-31684?

CVE-2021-31684 is a high-severity denial of service vulnerability in n/a, published on 1 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was discovered in the indexOf function of JSONParserByteArray in JSON Smart versions 1.3 and 2.4 which causes a denial of service (DOS) via a crafted web request.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-31684?

4 open source packages ship an affected version, including net.minidev:json-smart. It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `net.minidev:json-smart` | Maven | From 1.3.0 | 1.3.3 |
| `net.minidev:json-smart` | Maven | From 1.3.0 | 1.3.3 |
| `net.minidev:json-smart` | Maven | From 2.4.0 | 2.4.4 |
| `net.minidev:json-smart` | Maven | From 2.4.0 | 2.4.4 |

Products: Json-Smart Project Json-Smart-V1, Json-Smart Project Json-Smart-V2, Oracle Utilities Framework.

## How do I fix CVE-2021-31684?

Upgrade net.minidev:json-smart to a fixed version for your release line: 1.3.3 or 2.4.4.

## Is CVE-2021-31684 being exploited?

There is no known exploitation of CVE-2021-31684 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-27568](https://insights.sbomify.com/CVE-2021-27568/): Improper Check for Unusual or Exceptional Conditions in json-smart (medium 5.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31684 and fix it if it is affected.

What it is: CVE-2021-31684 is a high-severity denial of service vulnerability in n/a, published on 1 Jun 2021. 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-2021-31684 in the wild and no public exploit code.

Affected packages and fixed versions:
- net.minidev:json-smart (Maven): affected from 1.3.0; fixed in 1.3.3
- net.minidev:json-smart (Maven): affected from 1.3.0; fixed in 1.3.3
- net.minidev:json-smart (Maven): affected from 2.4.0; fixed in 2.4.4
- net.minidev:json-smart (Maven): affected from 2.4.0; fixed in 2.4.4

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-2021-31684/ (Markdown: https://insights.sbomify.com/CVE-2021-31684/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31684
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31684
- OSV: https://osv.dev/vulnerability/CVE-2021-31684

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31684/
Summaries are generated and may contain mistakes; the official description above is the record.