# CVE-2025-5256: Open Redirect vulnerability on user unlock path

> Attackers can redirect users to malicious sites via the user unlock endpoint, facilitating phishing attacks against Mautic users.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A: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:** 28 May 2025
- **Updated:** 28 May 2025
- **Also known as:** CVE-2025-48873, GHSA-6vx9-9r2g-8373

## What is CVE-2025-5256?

CVE-2025-5256 is a medium-severity vulnerability in Mautic, published on 28 May 2025. 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

SummaryThis advisory addresses an Open Redirection vulnerability in Mautic's user unlocking endpoint. This vulnerability could be exploited by an attacker to redirect legitimate users to malicious websites, potentially leading to phishing attacks or the delivery of exploit kits.

Open Redirection via returnUrl Parameter: An Open Redirection vulnerability exists in the /s/action/unlock/user.user/0 endpoint. The returnUrl parameter, intended for post-action redirection, is not properly validated. This allows an attacker to craft a URL that, when clicked by a user, redirects them to an arbitrary external website controlled by the attacker.

MitigationUpdate Mautic to a version that properly validates or sanitizes the returnUrl parameter to ensure that redirects only occur to trusted, internal URLs or explicitly whitelisted domains.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2025-5256?

6 open source packages ship an affected version, including mautic/core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mautic/core` | Packagist | From 1.0.0 | 4.4.16 |
| `mautic/core` | Packagist | From 1.0.0 | 4.4.16 |
| `mautic/core` | Packagist | From 5.0.0-alpha | 5.2.6 |
| `mautic/core` | Packagist | From 5.0.0-alpha | 5.2.6 |
| `mautic/core` | Packagist | From 6.0.0-alpha | 6.0.2 |
| `mautic/core` | Packagist | From 6.0.0-alpha | 6.0.2 |

## How do I fix CVE-2025-5256?

Upgrade mautic/core to a fixed version for your release line: 4.4.16, 5.2.6 or 6.0.2.

## Is CVE-2025-5256 being exploited?

There is no known exploitation of CVE-2025-5256 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-5256 and fix it if it is affected.

What it is: CVE-2025-5256 is a medium-severity vulnerability in Mautic, published on 28 May 2025. 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-2025-5256 in the wild and no public exploit code.

Affected packages and fixed versions:
- mautic/core (Packagist): affected from 1.0.0; fixed in 4.4.16
- mautic/core (Packagist): affected from 1.0.0; fixed in 4.4.16
- mautic/core (Packagist): affected from 5.0.0-alpha; fixed in 5.2.6
- mautic/core (Packagist): affected from 5.0.0-alpha; fixed in 5.2.6
- mautic/core (Packagist): affected from 6.0.0-alpha; fixed in 6.0.2
- mautic/core (Packagist): affected from 6.0.0-alpha; fixed in 6.0.2

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-2025-5256/ (Markdown: https://insights.sbomify.com/CVE-2025-5256/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-5256
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-5256
- OSV: https://osv.dev/vulnerability/CVE-2025-5256

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-5256/
Summaries are generated and may contain mistakes; the official description above is the record.