CVE-2023-45683 is a high-severity (CVSS 7.1) Cross-site Scripting (XSS) vulnerability in github.com/crewjam/saml. A fix is available for github.com/crewjam/saml — see the affected versions and patch details below.
Cross site scripting via missing binding syntax validation In ACS location in github.com/crewjam/saml
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-2023-45683.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/crewjam/samlReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The package does not validate the ACS Location URI according to the SAML binding being parsed.
If abused, this flaw allows attackers to register malicious Service Providers at the IdP and inject Javascript in the ACS endpoint definition, achieving Cross-Site-Scripting (XSS) in the IdP context during the redirection at the end of a SAML SSO Flow.
Consequently, an attacker may perform any authenticated action as the victim once the victim’s browser loaded the SAML IdP initiated SSO link for the malicious service provider.
Note: The severity is considered “High” because the SP registration is commonly an unrestricted operation in IdPs, hence not requiring particular permissions or publicly accessible to ease the IdP interoperability.
Patches
This issue is fixed in 0.4.14
Workarounds
Users of the package can perform external validation of URLs provided in SAML metadata, or restrict the ability for end-users to upload arbitrary metadata.
References
This issue was reported by Francesco Lacerenza from Doyensec.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/crewjam/saml | all versions | 0.4.14go get github.com/crewjam/saml@v0.4.14 |
Affected Products
samlsaml_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/crewjam/saml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/crewjam/saml to 0.4.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-45683 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2023-45683 in your dependencies?
Find it across Go, including transitive dependencies.