CVE-2026-34206
Captcha Protect: Reflected XSS in challenge page via unsanitized destination rendered with text/template
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.12.2
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- libops captcha-protect
fixed in 1.12.2