# CVE-2021-29623: Uninitialized variable bug in Exiv2

> An attacker can leak stack memory bytes by tricking a user into processing a crafted image file with the Exiv2 library.

- **Severity:** Low 3.6 (`CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 13 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** AZL-7212, CLEANSTART-2024-RH47389, DEBIAN-CVE-2021-29623, GHSA-6253-qjwm-3q4v, UBUNTU-CVE-2021-29623, openSUSE-SU-2024:12063-1

## What is CVE-2021-29623?

CVE-2021-29623 is a low-severity vulnerability in Exiv2 Exiv2, published on 13 May 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Exiv2 is a C++ library and a command-line utility to read, write, delete and modify Exif, IPTC, XMP and ICC image metadata. A read of uninitialized memory was found in Exiv2 versions v0.27.3 and earlier. Exiv2 is a command-line utility and C++ library for reading, writing, deleting, and modifying the metadata of image files. The read of uninitialized memory is triggered when Exiv2 is used to read the metadata of a crafted image file. An attacker could potentially exploit the vulnerability to leak a few bytes of stack memory, if they can trick the victim into running Exiv2 on a crafted image file. The bug is fixed in version v0.27.4.

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2021-29623?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `exiv2` | openSUSE:Tumbleweed | All versions | 0.27.5-2.1 |

Products: Exiv2 Exiv2, Fedoraproject Fedora.

## How do I fix CVE-2021-29623?

Upgrade to a fixed version.

## Is CVE-2021-29623 being exploited?

There is no known exploitation of CVE-2021-29623 in the wild and no public exploit code.

## Other vulnerabilities in Exiv2 Exiv2

- [CVE-2023-44398](https://insights.sbomify.com/CVE-2023-44398/): Out-of-bounds write in exiv2 (high 8.8)
- [CVE-2019-9143](https://insights.sbomify.com/CVE-2019-9143/): Denial of service in n/a (high 8.8)
- [CVE-2019-9144](https://insights.sbomify.com/CVE-2019-9144/): Denial of service in n/a (high 8.8)
- [CVE-2018-14046](https://insights.sbomify.com/CVE-2018-14046/): Memory corruption in n/a (high 8.8)
- [CVE-2017-12955](https://insights.sbomify.com/CVE-2017-12955/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-29623 and fix it if it is affected.

What it is: CVE-2021-29623 is a low-severity vulnerability in Exiv2 Exiv2, published on 13 May 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-29623 in the wild and no public exploit code.

Affected product: Exiv2 Exiv2. 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-2021-29623/ (Markdown: https://insights.sbomify.com/CVE-2021-29623/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-29623
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-29623
- OSV: https://osv.dev/vulnerability/CVE-2021-29623

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-29623/
Summaries are generated and may contain mistakes; the official description above is the record.