# CVE-2023-26966: Memory corruption in n/a

> A buffer overflow in libtiff allows attackers to execute arbitrary code or cause denial of service via a crafted TIFF file.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **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:** 29 Jun 2023
- **Updated:** 3 Nov 2025
- **Also known as:** AZL-27303, BELL-CVE-2023-26966, DEBIAN-CVE-2023-26966, GHSA-wg7m-6ff7-7pcj, UBUNTU-CVE-2023-26966

## What is CVE-2023-26966?

CVE-2023-26966 is a medium-severity memory corruption vulnerability in Libtiff Libtiff, published on 29 Jun 2023. 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

libtiff 4.5.0 is vulnerable to Buffer Overflow in uv_encode() when libtiff reads a corrupted little-endian TIFF file and specifies the output to be big-endian.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2023-26966?

It affects 1 product.


Products: Libtiff Libtiff.

## How do I fix CVE-2023-26966?

Upgrade to a fixed version.

## Is CVE-2023-26966 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-26966 exists.

## Other vulnerabilities in Libtiff Libtiff

- [CVE-2004-1308](https://insights.sbomify.com/CVE-2004-1308/): Integer overflow in n/a (critical 10.0)
- [CVE-2004-0929](https://insights.sbomify.com/CVE-2004-0929/): Memory corruption in n/a (critical 10.0)
- [CVE-2025-61144](https://insights.sbomify.com/CVE-2025-61144/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-9533](https://insights.sbomify.com/CVE-2016-9533/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-9534](https://insights.sbomify.com/CVE-2016-9534/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-26966 and fix it if it is affected.

What it is: CVE-2023-26966 is a medium-severity memory corruption vulnerability in Libtiff Libtiff, published on 29 Jun 2023. 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-26966 exists.

Affected product: Libtiff Libtiff. 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-2023-26966/ (Markdown: https://insights.sbomify.com/CVE-2023-26966/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-26966
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-26966
- OSV: https://osv.dev/vulnerability/CVE-2023-26966

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-26966/
Summaries are generated and may contain mistakes; the official description above is the record.