# CVE-2026-22186: Bio-Formats <= 8.3.0 XXE in Leica XLEF Metadata Parser

> Attackers can exploit an XXE vulnerability in Bio-Formats to read local files or cause denial of service via crafted Leica metadata files.

- **Severity:** Medium 4.6 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA: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:** No
- **Published:** 7 Jan 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-fcqj-76g3-q7qm, GHSA-x9vc-qh97-8gjp

## What is CVE-2026-22186?

CVE-2026-22186 is a medium-severity vulnerability in Open Microscopy Environment Bio-Formats, published on 7 Jan 2026. 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

Bio-Formats versions up to and including 8.3.0 contain an XML External Entity (XXE) vulnerability in the Leica Microsystems metadata parsing component (e.g., XLEF). The parser uses an insecurely configured DocumentBuilderFactory when processing Leica XML-based metadata files, allowing external entity expansion and external DTD loading. A crafted metadata file can trigger outbound network requests (SSRF), access local system resources where readable, or cause a denial of service during XML parsing.

Weakness: CWE-611 (Improper Restriction of XML External Entity Reference)

## Which versions are affected by CVE-2026-22186?

2 open source packages ship an affected version, including ome:pom-bio-formats. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ome:pom-bio-formats` | Maven | All versions to 8.3.0 | None |
| `ome:pom-bio-formats` | Maven | All versions to 8.3.0 | None |

Products: Openmicroscopy Bio-Formats.

## How do I fix CVE-2026-22186?

No fix has been published for CVE-2026-22186 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-22186 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-22186 exists.

## Other vulnerabilities in Open Microscopy Environment Bio-Formats

- [CVE-2026-22187](https://insights.sbomify.com/CVE-2026-22187/): Bio-Formats <= 8.3.0 Memoizer Unsafe Deserialization via .bfmemo Cache Files (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22186 and fix it if it is affected.

What it is: CVE-2026-22186 is a medium-severity vulnerability in Open Microscopy Environment Bio-Formats, published on 7 Jan 2026. 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-2026-22186 exists.

Affected packages and fixed versions:
- ome:pom-bio-formats (Maven): affected all versions up to 8.3.0; no fix listed
- ome:pom-bio-formats (Maven): affected all versions up to 8.3.0; no fix listed

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-2026-22186/ (Markdown: https://insights.sbomify.com/CVE-2026-22186/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22186
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22186
- OSV: https://osv.dev/vulnerability/CVE-2026-22186

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-22186/
Summaries are generated and may contain mistakes; the official description above is the record.