# CVE-2025-15581: Auth bypass in orthanc

> Attackers can bypass authentication to gain full administrative access to the Orthanc medical imaging server.

- **Severity:** Medium 4.7 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 18 Feb 2026
- **Updated:** 28 Feb 2026
- **Also known as:** DEBIAN-CVE-2025-15581, DLA-4494-1, GHSA-4wvv-g662-rjm9, UBUNTU-CVE-2025-15581

## What is CVE-2025-15581?

CVE-2025-15581 is a medium-severity authentication bypass vulnerability in orthanc-server orthanc, published on 18 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Orthanc versions before 1.12.10 are affected by an authorisation logic flaw in the application's HTTP Basic Authentication implementation. 

Successful exploitation could result in Privilege Escalation, potentially allowing full administrative access.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2025-15581?


## How do I fix CVE-2025-15581?

Upgrade to a fixed version.

## Is CVE-2025-15581 being exploited?

There is no known exploitation of CVE-2025-15581 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-15581 and fix it if it is affected.

What it is: CVE-2025-15581 is a medium-severity authentication bypass vulnerability in orthanc-server orthanc, published on 18 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-15581 in the wild and no public exploit code.

Affected product: orthanc-server orthanc. 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-2025-15581/ (Markdown: https://insights.sbomify.com/CVE-2025-15581/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-15581
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-15581
- OSV: https://osv.dev/vulnerability/CVE-2025-15581

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-15581/
Summaries are generated and may contain mistakes; the official description above is the record.