ApostropheCMS is an open-source Node.js content management system. Prior to 1.5.5 of the Form add-on, 1.2.1 of login-recaptcha, and 1.3.0 of login-hcaptcha, these three CAPTCHA integrations interpolate an unencoded user-supplied response token into the provider verification request. Crafted tokens can smuggle request parameters and disrupt CAPTCHA verification and CAPTCHA-gated form or login flows; automated bypass probing is possible, but a successful CAPTCHA bypass or secret disclosure is not established. This issue is fixed in Form 1.5.5, login-recaptcha 1.2.1, and login-hcaptcha 1.3.0.

Affected: npm: @apostrophecms/form, npm: @apostrophecms/login-recaptcha, npm: @apostrophecms/login-hcaptcha

**Summary** Form and login CAPTCHA verification interpolate the user-supplied widget token unencoded into the server-side verification URL/body, allowing a crafted token to inject query parameters into the reCAPTCHA/hCaptcha verify request.

**Details** - `packages/form/lib/recaptcha.js:39` — `recaptchaUri = 'https://www.google.com/recaptcha/api/siteverify?secret=${recaptchaSecret}&response=${input.recaptcha}'` - `packages/login-recaptcha/index.js:44` — same pattern for login - `packages/login-hcaptcha/index.js:47` — `body: 'response=${token}&secret=${secret}'`

**PoC** ``` input.recaptcha = 'attacker_token&secret=INJECTED_SECRET&something=1' → resulting verify URL: https://www.google.com/recaptcha/api/siteverify?secret=<real>&response=attacker_token&secret=INJECTED_SECRET&something=1 # (replicated exactly from recaptcha.js:39) ```

**Impact** Low: a crafted token smuggles extra `key=value` pairs (`secret`, extra `response`) into the outbound verify call, forcing verification failures (DoS of the captcha gate and of captcha-gated login/form flows) and enabling automated bypass probing; no secret exfiltration.

**Remediation** — Build the verify request with `URL` + `searchParams` (or `encodeURIComponent` on both `secret` and `response`), and validate the token against `^[A-Za-z0-9._-]{1,2048}$` before use.