# CVE-2026-56734: Zammad: Avatar Image URL Server-Side Request Forwarding

> Attackers can force the Zammad server to connect to internal network locations via malicious profile image URLs during federated authentication, enabling internal service probing and potential denial of service.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-q3cr-3wq3-29hx

## What is CVE-2026-56734?

CVE-2026-56734 is a medium-severity server-side request forgery vulnerability in zammad, published on 25 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, during federated authentication (OAuth/OIDC/SAML), a profile image URL from the external identity provider is fetched without verifying the target address. An actor who controls their profile at a connected provider may cause the server to connect to internal network locations. Response timing and error patterns differ between reachable and unreachable targets, allowing internal service probing. Worker processes may be blocked for several seconds per request. Requires a configured external authentication provider where the actor can modify their profile image URL. This issue is fixed in version 7.0.2.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-56734?


## How do I fix CVE-2026-56734?

No fix has been published for CVE-2026-56734 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-56734 being exploited?

There is no known exploitation of CVE-2026-56734 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56734 and fix it if it is affected.

What it is: CVE-2026-56734 is a medium-severity server-side request forgery vulnerability in zammad, published on 25 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-56734 in the wild and no public exploit code.

Affected product: zammad. 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-2026-56734/ (Markdown: https://insights.sbomify.com/CVE-2026-56734/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56734
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56734
- OSV: https://osv.dev/vulnerability/CVE-2026-56734

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56734/
Summaries are generated and may contain mistakes; the official description above is the record.