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)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.003 (23.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 23.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Libops Captcha-Protect — versions < 1.12.2
- Libops Captcha Protect
Weakness classification (CWE)
References
- github.com/libops/captcha-protect/security/advisories/GHSA-ph62-4j5g-2q4r (Patch, Mitigation, Vendor Advisory)
- github.com/libops/captcha-protect/commit/eef6211ecd1147273be484d913b81c68c0bd8d… (Patch)
- github.com/libops/captcha-protect/releases/tag/v1.12.2 (Product, 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.