CVE-2025-5256 — mautic/core
MEDIUMCVE-2025-5256 is a medium-severity (CVSS 5.4) Open Redirect vulnerability in mautic/core. A fix is available for mautic/core — see the affected versions and patch details below.
Mautic has an Open Redirect vulnerability on user unlock path.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-5256.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-5256 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
mautic/core🐘mautic/core🐘mautic/coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
This 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.
Mitigation
Update 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | mautic/core | ≥ 1.0.0&&< 4.4.16 | 4.4.16composer require mautic/core:^4.4.16 |
| 🐘Packagist | mautic/core | ≥ 5.0.0-alpha&&< 5.2.6 | 5.2.6composer require mautic/core:^5.2.6 |
| 🐘Packagist | mautic/core | ≥ 6.0.0-alpha&&< 6.0.2 | 6.0.2composer require mautic/core:^6.0.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mautic/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mautic/core to 4.4.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-5256 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-5256 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-5256. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-5256 in your dependencies?
O3 Security finds CVE-2025-5256 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.