A command injection vulnerability was discovered in the HNAP1 protocol in D-Link DIR-823G devices with firmware V1.0.2B05. An attacker is able to execute arbitrary web scripts via shell metacharacters in the Captcha field to Login.

Zoho ManageEngine ADSelfService Plus version 6103 and prior allows CAPTCHA bypass due to improper parameter validation.

The Contact Form 7 Captcha WordPress plugin before 0.0.9 does not have any CSRF check in place when saving its settings, allowing attacker to make a logged in user with the manage_options change them. Furthermore, the settings are not escaped when output in attributes, leading to a Stored Cross-Site Scripting issue.

A local file inclusion vulnerability was discovered in the captcha function in Monstra 3.0.4 which allows remote attackers to execute arbitrary PHP code.

The SimpleCaptcha implementation in Liferay Portal 7.3.4, 7.3.5 and Liferay DXP 7.3 before fix pack 1 does not invalidate CAPTCHA answers after it is used, which allows remote attackers to repeatedly perform actions protected by a CAPTCHA challenge by reusing the same CAPTCHA answer.

Unvalidated input and lack of output encoding in the WP Shieldon WordPress plugin, version 1.6.3 and below, leads to Unauthenticated Reflected Cross-Site Scripting (XSS) when the CAPTCHA page is shown could lead to privileged escalation.

The login page on D-Link DIR-615 T1 20.10 devices allows remote attackers to bypass the CAPTCHA protection mechanism and conduct brute-force attacks.

Easy!Appointments 1.3.0 has a Guessable CAPTCHA issue.

On certain TOTOLINK Realtek SDK based routers, the CAPTCHA text can be retrieved via an {"topicurl":"setting/getSanvas"} POST to the boafrm/formLogin URI, leading to a CAPTCHA bypass. (Also, the CAPTCHA text is not needed once the attacker has determined valid credentials. The attacker can perform router actions via HTTP requests with Basic Authentication.) This affects A3002RU through 2.0.0, A702R through 2.1.3, N301RT through 2.1.6, N302R through 3.4.0, N300RT through 3.4.0, N200RE through 4.0.0, N150RT through 3.4.0, and N100RE through 3.4.0.

AVTECH AVN801 DVR has a security bypass via the administration login captcha

A vulnerability in web interface of the Cisco Webex Event Center, Cisco Webex Meeting Center, Cisco Webex Support Center, and Cisco Webex Training Center could allow an unauthenticated, remote attacker to guess account usernames. The vulnerability is due to missing CAPTCHA protection in certain URLs. An attacker could exploit this vulnerability by sending a crafted request to the web interface. A successful exploit could allow the attacker to know if a given username is valid and find the real name of the user.

The sr_freecap (aka freeCap CAPTCHA) extension 2.4.5 and below and 2.5.2 and below for TYPO3 fails to sanitize user input, which allows execution of arbitrary Extbase actions, resulting in Remote Code Execution.

In Knowage through 6.1.1, the sign up page does not invalidate a valid CAPTCHA token. This allows for CAPTCHA bypass in the signup page.

The wpgform plugin before 0.94 for WordPress has eval injection in the CAPTCHA calculation.

Directus 7 API before 2.2.2 has insufficient anti-automation, as demonstrated by lack of a CAPTCHA in core/Directus/Services/AuthService.php and endpoints/Auth.php.

text/impl/DefaultTextCreator.java, text/impl/ChineseTextProducer.java, and text/impl/FiveLetterFirstNameTextCreator.java in kaptcha 2.3.2 use the Random (rather than SecureRandom) function for generating CAPTCHA values, which makes it easier for remote attackers to bypass intended access restrictions via a brute-force approach.

LG SuperSign CMS allows authentication bypass because the CAPTCHA requirement is skipped if a captcha:pass cookie is sent, and because the PIN is limited to four digits.

phpMyFAQ before 2.8.13 allows remote attackers to bypass the CAPTCHA protection mechanism by replaying the request.

An issue was discovered in the ajax-bootmodal-login plugin 1.4.3 for WordPress. The register form, login form, and password-recovery form require solving a CAPTCHA to perform actions. However, this is required only once per user session, and therefore one could send as many requests as one wished by automation.

Processing malformed SOAP messages when performing the HNAP Login action causes a buffer overflow in the stack in some D-Link DIR routers. The vulnerable XML fields within the SOAP body are: Action, Username, LoginPassword, and Captcha. The following products are affected: DIR-823, DIR-822, DIR-818L(W), DIR-895L, DIR-890L, DIR-885L, DIR-880L, DIR-868L, and DIR-850L.