Reflected XSS in go-httpbin due to unrestricted client control over Content-Type

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

1.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U · score source

EPSS

• CVE-2025-45286: 0.27% estimated exploitation activity in the next 30 days; percentile 18.91 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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: 1. Visit one of the above mentioned URLs. 2. 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

Published by the source

21 Mar 2025, 22:29 UTC

Last modified by the source

2 Jan 2026, 20:32 UTC

Source last checked

26 Oct 2026, 15:14 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-528q-4pgm-wvg2

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# Patch Next advisory brief: CVE-2025-45286

Advisory: Reflected XSS in go-httpbin due to unrestricted client control over Content-Type
IDs: CVE-2025-45286, GHSA-528q-4pgm-wvg2
Record: https://patchnext.com/advisories/cve-2025-45286 (revision 1, source checked 26 Oct 2026, 15:14 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 1.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/mccutchen/go-httpbin/v2 2.18.0; github.com/mccutchen/go-httpbin 2.18.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/mccutchen/go-httpbin/v2: affected < 2.18.0; fixed in 2.18.0
- Go github.com/mccutchen/go-httpbin: affected < 2.18.0; fixed in 2.18.0

## Suggested inspection (read-only)
- Go github.com/mccutchen/go-httpbin/v2: check the installed version with your package manager.
- Go github.com/mccutchen/go-httpbin: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/mccutchen/go-httpbin/v2, github.com/mccutchen/go-httpbin.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-528q-4pgm-wvg2 (GitHub-reviewed advisory GHSA-528q-4pgm-wvg2 lists affected ranges: Go github.com/mccutchen/go-httpbin >=0 =0 <2.18.0)

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