GHSA-mrqg-mwh7-q94j
HIGHHost header injection in the password reset
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.
Blast Radius
pimcore/admin-ui-classic-bundleReal-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
The password reset functionality sends to the the user requesting a password change an email containing an URL to reset its password.
The URL sent contains a unique token, valid during 24 hours, allowing the user to reset its password. This token is highly sensitive ; as an attacker able to retrieve it would be able to resets the user's password.
It was identified during the audit that the reset-password URL is crafted using the "Host" HTTP header of the request sent to request a password reset.
This way, an external attacker could send password requests for users, but specify a "Host" header of a website that they control. If the user receiving the mail clicks on the link, the attacker would retrieve the reset token of the victim and perform account takeover.
Details
This attack required the server to serve Pimcore on arbitrary "Host". This configuration would be plausible if the attacker is already behind the reverse proxy. During the assessment of my client, their instance was accepting any Host header, and they did not received security recommendations that they should restrict this while installing Pimcore.
From what I understood of Pimcore, the vulnerability is in the "admin-ui-classic-bundle", in the file src/Controller/Admin/UserController.php.
The following screenshots provide evidences of the vulnerability. The environment of the test is : dockerized Pimcore v11.1.1 on default configuration (https://pimcore.com/docs/platform/Pimcore/Getting_Started/Installation/Docker_Based_Installation/).
PoC
Remediation
Create a variable that sets the server host. Don't enable password reset functionality while this variable is not set ; or make sure that the administrator knows what they are doing.
I believe that just documenting that the server should not serve on any Host would not be enough to enforce a remediation to this vulnerability.
The Snipe-IT project managed this same issue by creating a "APP_ALLOW_INSECURE_HOSTS" variable, and retrieving the app absolute URL from a config file : https://github.com/snipe/snipe-it/commit/0c4768fd2a11ac26a61814cef23a71061bfd8bcc
Impact
Could lead to a 1-click account takeover
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | pimcore/admin-ui-classic-bundle | all versions | 1.2.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pimcore/admin-ui-classic-bundle. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update pimcore/admin-ui-classic-bundle to 1.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mrqg-mwh7-q94j 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 pinpoints whether GHSA-mrqg-mwh7-q94j is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-mrqg-mwh7-q94j. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-mrqg-mwh7-q94j in your dependencies?
O3 detects GHSA-mrqg-mwh7-q94j across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.