How severe is GHSA-mcxr-fx5f-96qq?

No CVSS score has been assigned to GHSA-mcxr-fx5f-96qq yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-mcxr-fx5f-96qq?

GHSA-mcxr-fx5f-96qq affects the following packages: concrete5/core (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-mcxr-fx5f-96qq?

Update concrete5/core to 8.5.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mcxr-fx5f-96qq is resolved across your whole dependency graph.

How do I detect GHSA-mcxr-fx5f-96qq in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for concrete5/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-mcxr-fx5f-96qq if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is GHSA-mcxr-fx5f-96qq actively exploited in the wild?

No public exploit code has been indexed for GHSA-mcxr-fx5f-96qq yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-mcxr-fx5f-96qq?

GHSA-mcxr-fx5f-96qq has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-mcxr-fx5f-96qq?

GHSA-mcxr-fx5f-96qq is classified as Server-Side Request Forgery (SSRF) (CWE-918). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-mcxr-fx5f-96qq published, and has it been updated?

GHSA-mcxr-fx5f-96qq was published on November 23, 2021 and was last updated on December 2, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

Server-Side Request Forgery in Concrete CMS

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐘concrete5/core

Real-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

Concrete CMS (formerly concrete5) versions below 8.5.7 has a SSRF mitigation bypass using DNS Rebind attack giving an attacker the ability to fetch cloud IAAS (ex AWS) IAM keys.To fix this Concrete CMS no longer allows downloads from the local network and specifies the validated IP when downloading rather than relying on DNS.Discoverer: Adrian Tiron from FORTBRIDGE ( https://www.fortbridge.co.uk/ )The Concrete CMS team gave this a CVSS 3.1 score of 3.5 AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N . Please note that Cloud IAAS provider mis-configurations are not Concrete CMS vulnerabilities. A mitigation for this vulnerability is to make sure that the IMDS configurations are according to a cloud provider's best practices.This fix is also in Concrete version 9.0.0

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`concrete5/core`	all versions	8.5.7`composer require concrete5/core:^8.5.7`

Affected Products

1 product · 1 configurations

Application

concrete cmsconcretecms

< 8.5.7

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for concrete5/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update concrete5/core to 8.5.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mcxr-fx5f-96qq is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

Concrete CMS (formerly concrete5) versions below 8.5.7 has a SSRF mitigation bypass using DNS Rebind attack giving an attacker the ability to fetch cloud IAAS (ex AWS) IAM keys.To fix this Concrete CMS no longer allows downloads from the local network and specifies the validated IP when downloading rather than relying on DNS.Discoverer.

O3 Security · Impact-Aware SCA

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Server-Side Request Forgery in Concrete CMSGHSA-mcxr-fx5f-96qq