CVE-2025-45286 is a medium-severity (CVSS 6.1) CWE-80 vulnerability in github.com/mccutchen/go-httpbin. A fix is available for github.com/mccutchen/go-httpbin — see the affected versions and patch details below.
Reflected XSS in go-httpbin due to unrestricted client control over Content-Type
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-45286.
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/mccutchen/go-httpbin🐹github.com/mccutchen/go-httpbin/v2Real-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
Description
The go-httpbin framework is vulnerable to XSS as the user can control the Response Content-Type from GET parameter. This allows attacker to execute cross site scripts in victims browser.
Affected URLs:
/response-headers?Content-Type=text/html&xss=%3Cimg/src/onerror=alert(%27xss%27)%3E/base64/PGltZy9zcmMvb25lcnJvcj1hbGVydCgneHNzJyk+?content-type=text/html/base64/decode/PGltZy9zcmMvb25lcnJvcj1hbGVydCgneHNzJyk+?content-type=text/html
Steps to reproduce:
- Visit one of the above mentioned URLs.
- XSS window will popup
Suggested fix
- Allow Only Safe Content-Type Values Or give users option to define whitelisted Content-Type headers
Criticality
The following can be major impacts of the issue:
- Access to victim's sensitive Personal Identifiable Information.
- Access to CSRF token
- Cookie injection
- Phishing
- And any other thing Javascript can perform
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/mccutchen/go-httpbin | all versions | 2.18.0go get github.com/mccutchen/go-httpbin@v2.18.0 |
| 🐹Go | github.com/mccutchen/go-httpbin/v2 | all versions | 2.18.0go get github.com/mccutchen/go-httpbin/v2@v2.18.0 |
Affected Products
go-httpbinhttpbingoDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mccutchen/go-httpbin, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/mccutchen/go-httpbin to 2.18.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-45286 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-2025-45286 in your dependencies?
Find it across Go, including transitive dependencies.