# CVE-2026-67549: OpenImageIO: TIFF 1-bit CMYK bit conversion heap out-of-bounds write

> A heap out-of-bounds write in OpenImageIO allows attackers to cause memory corruption and potentially execute code via crafted TIFF files.

- **Severity:** High 7.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 18 Sep 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-3wxw-rqhw-j2w4, UBUNTU-CVE-2026-67549

## What is CVE-2026-67549?

CVE-2026-67549 is a high-severity memory corruption vulnerability in Openimageio Openimageio, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.1.16.0, A crafted 1-bit contiguous cmyk tiff is exposed through a native uint1 imagespec, so callers allocate a bit-packed buffer. tiffinput::read_native_scanline_locked() nevertheless invokes tiffinput::bit_convert() with 8-bit output and writes one expanded byte per value into that smaller buffer, resulting in a heap out-of-bounds write and memory corruption. The affected implementation is identified by src/tiff.imageio/tiffinput.cpp, TIFFInput::bit_convert(), TIFFInput::read_native_scanline_locked(), PHOTOMETRIC_SEPARATED, 1-bit CMYK, and native uint1 ImageSpec, which define the relevant source path, functions, state, and trigger. This issue is fixed in 3.1.16.0.

Weakness: CWE-787 (Out-of-bounds Write), CWE-131 (Incorrect Calculation of Buffer Size), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-67549?

It affects 1 product.


Products: Openimageio Openimageio.

## How do I fix CVE-2026-67549?

Upgrade to a fixed version.

## Is CVE-2026-67549 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67549 exists.

## Other vulnerabilities in Openimageio Openimageio

- [CVE-2024-55192](https://insights.sbomify.com/CVE-2024-55192/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-55194](https://insights.sbomify.com/CVE-2024-55194/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-42299](https://insights.sbomify.com/CVE-2023-42299/): Memory corruption in n/a (critical 9.8)
- [CVE-2022-38143](https://insights.sbomify.com/CVE-2022-38143/): Memory corruption in OpenImageIO (critical 9.8)
- [CVE-2026-43908](https://insights.sbomify.com/CVE-2026-43908/): OpenImageIO: Signed integer overflow in ConvertCbYCrYToRGB leads to heap out-of-bounds write in DPX 4:2:2 decoder (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-67549 and fix it if it is affected.

What it is: CVE-2026-67549 is a high-severity memory corruption vulnerability in Openimageio Openimageio, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, 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-2026-67549 exists.

Affected product: Openimageio Openimageio. 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-2026-67549/ (Markdown: https://insights.sbomify.com/CVE-2026-67549/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-67549
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-67549
- OSV: https://osv.dev/vulnerability/CVE-2026-67549

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-67549/
Summaries are generated and may contain mistakes; the official description above is the record.