# CVE-2021-21235: Infinite loop in parsing PNG files in

> An attacker can cause a denial of service via an infinite loop by providing a crafted PNG file to the kamadak-exif library.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Jan 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-px9g-8hgv-jvg2, RUSTSEC-2021-0143, UBUNTU-CVE-2021-21235

## What is CVE-2021-21235?

CVE-2021-21235 is a medium-severity denial of service vulnerability in kamadak exif-rs, published on 6 Jan 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

kamadak-exif is an exif parsing library written in pure Rust. In kamadak-exif version 0.5.2, there is an infinite loop in parsing crafted PNG files. Specifically, reader::read_from_container can cause an infinite loop when a crafted PNG file is given. This is fixed in version 0.5.3. No workaround is available. Applications that do not pass files with the PNG signature to Reader::read_from_container are not affected.

Weakness: CWE-835 (Loop with Unreachable Exit Condition), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2021-21235?

3 open source packages ship an affected version, including kamadak-exif. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `kamadak-exif` | crates.io | From 0.5.2 | 0.5.3 |
| `kamadak-exif` | crates.io | From 0.5.2 | 0.5.3 |
| `kamadak-exif` | crates.io | From 0.5.2 | 0.5.3 |

Products: Kamadak-Exif Project Kamadak-Exif.

## How do I fix CVE-2021-21235?

Upgrade kamadak-exif to 0.5.3 or later.

## Is CVE-2021-21235 being exploited?

There is no known exploitation of CVE-2021-21235 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21235 and fix it if it is affected.

What it is: CVE-2021-21235 is a medium-severity denial of service vulnerability in kamadak exif-rs, published on 6 Jan 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-21235 in the wild and no public exploit code.

Affected packages and fixed versions:
- kamadak-exif (crates.io): affected from 0.5.2; fixed in 0.5.3
- kamadak-exif (crates.io): affected from 0.5.2; fixed in 0.5.3
- kamadak-exif (crates.io): affected from 0.5.2; fixed in 0.5.3

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-2021-21235/ (Markdown: https://insights.sbomify.com/CVE-2021-21235/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21235
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21235
- OSV: https://osv.dev/vulnerability/CVE-2021-21235

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21235/
Summaries are generated and may contain mistakes; the official description above is the record.