XSS in Libops Captcha-Protect
CVE-2026-34206
Captcha Protect is a Traefik middleware to add an anti-bot challenge to individual IPs in a subnet when traffic spikes are detected from that subnet. Prior to version 1.12.2, a reflected cross-site scripting (XSS) vulnerability exists in github.com/libops/captcha-protect. The challenge page accepted a client-supplied destination value and rendered it into HTML using Go's text/template. Because text/template does not perform contextual HTML escaping, an attacker could supply a crafted destination value that breaks out of the hidden input attribute and injects arbitrary script into the challenge page. This issue has been patched in version 1.12.2.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.002 (8.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Libops Captcha-protect — versions < 1.12.2
- Libops Captcha_protect
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Mitigation, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-34206?
- CVE-2026-34206 is a medium-severity vulnerability in Libops Captcha-Protect, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-03-31.
- How severe is CVE-2026-34206?
- Medium severity. CVSS v3 base score is 6.1 out of 10.