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CWE-804

Guessable CAPTCHA

11 CVEs Avg CVSS 5.6 MITRE
0
CRITICAL
1
HIGH
10
MEDIUM
0
LOW
2
POC
0
KEV

Monthly

CVE-2026-49953 Jun 15, 18:45 MEDIUM POC This Month

CAPTCHA challenge controls in Discuz! X5.0 (releases 20260320-20260501) can be reliably defeated by unauthenticated remote attackers who harvest samples from exposed forum endpoints and train a custom optical character recognition model to predict challenge text. The underlying weakness - CWE-804 - stems from a limited, predictable character set and insufficient visual distortion in generated images, enabling automation of login, registration, and other abuse-protected flows. Critically, a publicly available exploit exists and KarmaInsecurity has documented chaining this bypass with a race condition to achieve full remote code execution, substantially elevating practical risk beyond the standalone CVSS 4.0 score of 6.9.

Authentication Bypass Discuz Discuz X5 0
NVD
CVSS 4.0
6.9
EPSS
0.4%
CVE-2026-40935 Apr 21, 23:16 PHP MEDIUM This Month

CAPTCHA bypass in WWBN AVideo 29.0 and prior enables unauthenticated attackers to defeat bot protection on user registration, password recovery, and contact form endpoints in at most 33 HTTP requests per session. Two cooperating flaws are responsible: the getCaptcha.php endpoint accepts the word-length parameter directly from the query string without bounds checking, allowing an attacker to force a 1-character CAPTCHA, and failed validation attempts do not invalidate the stored session token, enabling exhaustive brute-forcing of the 33-symbol alphabet. No CISA KEV listing exists, though SSVC rates the attack as automatable with POC-level exploitation, and the effective attack complexity is trivially low regardless of the AC:L CVSS rating.

PHP Information Disclosure Avideo Wwbn
NVD GitHub
CVSS 3.1
5.3
EPSS
0.0%
CVE-2025-70129 Mar 10, 20:16 MEDIUM This Month

If the anti spam-captcha functionality in PluXml versions 5.8.22 and earlier is enabled, a captcha challenge is generated with a format that can be automatically recognized for articles, such that an automated script is able to solve this anti-spam mechanism trivially and publish spam comments. [CVSS 5.3 MEDIUM]

Information Disclosure Pluxml
NVD GitHub VulDB
CVSS 3.1
5.3
EPSS
0.0%
CVE-2026-27411 Mar 05, 06:16 MEDIUM This Month

The SiteGuard WP Plugin for WordPress through version 1.7.9 contains a guessable CAPTCHA implementation that allows attackers to bypass security protections without authentication. This vulnerability enables attackers to circumvent the plugin's functionality controls and potentially gain unauthorized access to protected resources or perform actions that should be restricted.

WordPress Authentication Bypass Wordpress Plugin
NVD
CVSS 3.1
5.4
EPSS
0.0%
CVE-2025-32036 Apr 08, 18:16 MEDIUM PATCH This Month

DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. Rated medium severity (CVSS 4.2), this vulnerability is remotely exploitable, no authentication required.

Information Disclosure Microsoft Dotnetnuke Dnnsoftware
NVD GitHub
CVSS 3.1
4.2
EPSS
0.2%
CVE-2025-1262 Feb 25, 13:15 MEDIUM PATCH This Month

The Advanced Google reCaptcha plugin for WordPress is vulnerable to CAPTCHA Bypass in versions up to, and including, 1.27 . Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

PHP WordPress Authentication Bypass Google Advanced Google Recaptcha +2
NVD
CVSS 3.1
5.3
EPSS
0.3%
CVE-2024-31295 May 17, 09:15 MEDIUM This Month

Guessable CAPTCHA vulnerability in BestWebSoft Captcha by BestWebSoft allows Functionality Bypass.2.0. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Authentication Bypass
NVD
CVSS 3.1
5.3
EPSS
0.4%
CVE-2024-30540 May 17, 09:15 MEDIUM This Month

Guessable CAPTCHA vulnerability in Guido VS Contact Form allows Functionality Bypass.7. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Authentication Bypass
NVD
CVSS 3.1
5.3
EPSS
0.5%
CVE-2023-6963 Feb 05, 22:15 MEDIUM PATCH This Month

The Getwid - Gutenberg Blocks plugin for WordPress is vulnerable to CAPTCHA Bypass in versions up to, and including, 2.0.4. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

WordPress Authentication Bypass Getwid Wordpress Plugin Motopress
NVD VulDB
CVSS 3.1
5.3
EPSS
0.1%
CVE-2022-4036 Nov 29, 21:15 MEDIUM PATCH This Month

The Appointment Hour Booking plugin for WordPress is vulnerable to CAPTCHA bypass in versions up to, and including, 1.3.72. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

WordPress Authentication Bypass Appointment Hour Booking Wordpress Plugin Dwbooster
NVD VulDB
CVSS 3.1
5.3
EPSS
0.1%
EPSS 0% CVSS 6.9
MEDIUM POC This Month

CAPTCHA challenge controls in Discuz! X5.0 (releases 20260320-20260501) can be reliably defeated by unauthenticated remote attackers who harvest samples from exposed forum endpoints and train a custom optical character recognition model to predict challenge text. The underlying weakness - CWE-804 - stems from a limited, predictable character set and insufficient visual distortion in generated images, enabling automation of login, registration, and other abuse-protected flows. Critically, a publicly available exploit exists and KarmaInsecurity has documented chaining this bypass with a race condition to achieve full remote code execution, substantially elevating practical risk beyond the standalone CVSS 4.0 score of 6.9.

Authentication Bypass Discuz Discuz X5 0
NVD
EPSS 0% CVSS 5.3
MEDIUM This Month

CAPTCHA bypass in WWBN AVideo 29.0 and prior enables unauthenticated attackers to defeat bot protection on user registration, password recovery, and contact form endpoints in at most 33 HTTP requests per session. Two cooperating flaws are responsible: the getCaptcha.php endpoint accepts the word-length parameter directly from the query string without bounds checking, allowing an attacker to force a 1-character CAPTCHA, and failed validation attempts do not invalidate the stored session token, enabling exhaustive brute-forcing of the 33-symbol alphabet. No CISA KEV listing exists, though SSVC rates the attack as automatable with POC-level exploitation, and the effective attack complexity is trivially low regardless of the AC:L CVSS rating.

PHP Information Disclosure Avideo +1
NVD GitHub
EPSS 0% CVSS 5.3
MEDIUM This Month

If the anti spam-captcha functionality in PluXml versions 5.8.22 and earlier is enabled, a captcha challenge is generated with a format that can be automatically recognized for articles, such that an automated script is able to solve this anti-spam mechanism trivially and publish spam comments. [CVSS 5.3 MEDIUM]

Information Disclosure Pluxml
NVD GitHub VulDB
EPSS 0% CVSS 5.4
MEDIUM This Month

The SiteGuard WP Plugin for WordPress through version 1.7.9 contains a guessable CAPTCHA implementation that allows attackers to bypass security protections without authentication. This vulnerability enables attackers to circumvent the plugin's functionality controls and potentially gain unauthorized access to protected resources or perform actions that should be restricted.

WordPress Authentication Bypass Wordpress Plugin
NVD
EPSS 0% CVSS 4.2
MEDIUM PATCH This Month

DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. Rated medium severity (CVSS 4.2), this vulnerability is remotely exploitable, no authentication required.

Information Disclosure Microsoft Dotnetnuke +1
NVD GitHub
EPSS 0% CVSS 5.3
MEDIUM PATCH This Month

The Advanced Google reCaptcha plugin for WordPress is vulnerable to CAPTCHA Bypass in versions up to, and including, 1.27 . Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

PHP WordPress Authentication Bypass +4
NVD
EPSS 0% CVSS 5.3
MEDIUM This Month

Guessable CAPTCHA vulnerability in BestWebSoft Captcha by BestWebSoft allows Functionality Bypass.2.0. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Authentication Bypass
NVD
EPSS 0% CVSS 5.3
MEDIUM This Month

Guessable CAPTCHA vulnerability in Guido VS Contact Form allows Functionality Bypass.7. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Authentication Bypass
NVD
EPSS 0% CVSS 5.3
MEDIUM PATCH This Month

The Getwid - Gutenberg Blocks plugin for WordPress is vulnerable to CAPTCHA Bypass in versions up to, and including, 2.0.4. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

WordPress Authentication Bypass Getwid +2
NVD VulDB
EPSS 0% CVSS 5.3
MEDIUM PATCH This Month

The Appointment Hour Booking plugin for WordPress is vulnerable to CAPTCHA bypass in versions up to, and including, 1.3.72. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

WordPress Authentication Bypass Appointment Hour Booking +2
NVD VulDB

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