Cyber Resilience

CVE-2026-3214

Auth Bypass in Arnabdotorg Captcha ≤ 8.x-1.17

Auth Bypass
Published
25 March 2026
Modified
02 April 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.0027 19th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-3214 is a medium-severity Authentication Bypass Using an Alternate Path or Channel (CWE-288) vulnerability in Arnabdotorg Captcha. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 19th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and IA-2 (Identification and Authentication (Organizational Users)) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

Authentication Bypass Using an Alternate Path or Channel vulnerability in Drupal CAPTCHA allows Functionality Bypass.This issue affects CAPTCHA: from 0.0.0 before 1.17.0, from 2.0.0 before 2.0.10.

CWE(s)
CWE-288

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Why these techniques?

Direct exploitation of auth bypass vuln in public-facing Drupal web app (CAPTCHA module).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2025-2747Shared CWE-288
CVE-2025-7038Shared CWE-288
CVE-2025-5060Shared CWE-288
CVE-2025-9313Shared CWE-288
CVE-2026-54817Shared CWE-288
CVE-2026-40785Shared CWE-288
CVE-2026-40781Shared CWE-288
CVE-2026-42629Shared CWE-288
CVE-2026-39450Shared CWE-288
CVE-2026-25439Shared CWE-288

Affected Assets

arnabdotorg
captcha
≤ 8.x-1.17 · 2.0.0 — 2.0.10

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • IA-2 Identification and Authentication (Organizational Users)
  • AC-6 Least Privilege
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 7 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.3
  • V6.6.1
  • V12.1.3

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match
prevent

Directly enforces that protected Drupal functionality may only be reached after successful CAPTCHA authentication, blocking alternate-path bypasses.

IA-2 Identification and Authentication (Organizational Users) good match
prevent

Requires verified identification and authentication before granting access, eliminating the unauthenticated alternate channel described in CWE-288.

AC-6 Least Privilege partial match
prevent

Restricts the privileges obtainable via the bypassed CAPTCHA path, limiting the impact of any successful functionality bypass.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 full match
prevents

Requiring authentication on every channel and path directly eliminates alternate-path bypasses.

PR.AA-05 mostly match
prevents

Enforcing authorizations and least privilege across all access vectors prevents unauthenticated alternate paths.

PR.IR-01 mostly match
prevents

Protecting networks and environments from unauthorized logical access blocks bypass via undocumented channels.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing can detect alternate-path bypasses but does not prevent them in production.

A.8.5 Secure authentication mostly match
degrades

Secure authentication control directly mitigates bypass by requiring strong, consistent authentication on all paths.

A.5.15 Access control partial match
prevents

Access control policy directly addresses alternate authentication paths by requiring all channels to enforce authentication.

A.5.17 Authentication information partial match
degrades

Authentication information management ensures credentials and mechanisms are consistently applied across all access paths.

A.5.18 Access rights partial match
prevents

Access rights provisioning and review prevent bypass via unmonitored or alternate channels.

A.8.2 Privileged access rights partial match
prevents

Privileged access rights control reduces risk of bypass through elevated or alternate paths.

References