# CVE-2026-1837: libjxl: Out-of-bounds write in grayscale color transformation when using LCMS2

> A crafted file triggers an out-of-bounds write in libjxl when using LCMS2, potentially allowing code execution or denial of service.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **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:** 11 Feb 2026
- **Updated:** 15 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-1837, GHSA-76gx-97cq-65f5, UBUNTU-CVE-2026-1837, openSUSE-SU-2026:10271-1

## What is CVE-2026-1837?

CVE-2026-1837 is a high-severity memory corruption vulnerability in Google libjxl, published on 11 Feb 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

A specially-crafted file can cause libjxl's decoder to write pixel data to uninitialized unallocated memory. Soon after that data from another uninitialized unallocated region is copied to pixel data.

This can be done by requesting color transformation of grayscale images to another grayscale color space. Buffers allocated for 1-float-per-pixel are used as if they are allocated for 3-float-per-pixel. That happens only if LCMS2 is used as CMS engine. There is another CMS engine available (selected by build flags).

Weakness: CWE-787 (Out-of-bounds Write), CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-805 (Buffer Access with Incorrect Length Value)

## Which versions are affected by CVE-2026-1837?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libjxl` | openSUSE:Tumbleweed | All versions | 0.11.2-1.1 |

Products: Libjxl Project Libjxl.

## How do I fix CVE-2026-1837?

Apply the vendor's patch.

## Is CVE-2026-1837 being exploited?

There is no known exploitation of CVE-2026-1837 in the wild and no public exploit code.

## Other vulnerabilities in Google libjxl

- [CVE-2021-27804](https://insights.sbomify.com/CVE-2021-27804/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-35790](https://insights.sbomify.com/CVE-2023-35790/): Integer overflow in n/a (high 7.5)
- [CVE-2021-36691](https://insights.sbomify.com/CVE-2021-36691/): Denial of service in n/a (high 7.5)
- [CVE-2024-11403](https://insights.sbomify.com/CVE-2024-11403/): Out of Bounds Memory Read/Write in libjxl (medium 6.9)
- [CVE-2024-11498](https://insights.sbomify.com/CVE-2024-11498/): Resource exhaustion via Stack overflow in libjxl (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-1837 and fix it if it is affected.

What it is: CVE-2026-1837 is a high-severity memory corruption vulnerability in Google libjxl, published on 11 Feb 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: There is no known exploitation of CVE-2026-1837 in the wild and no public exploit code.

Affected product: Google libjxl. 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-2026-1837/ (Markdown: https://insights.sbomify.com/CVE-2026-1837/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-1837
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-1837
- OSV: https://osv.dev/vulnerability/CVE-2026-1837

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-1837/
Summaries are generated and may contain mistakes; the official description above is the record.