6.9
MEDIUM CVSS 4.0
CVE-2026-56338
Capgo - Denial of Service in 2FA Email Verification via /auth/v1/otp Endpoint
Description

Capgo before 12.128.2 contains a denial of service vulnerability in the /auth/v1/otp endpoint that prevents email verification for two-factor authentication due to captcha validation failures. Authenticated users cannot complete 2FA enrollment as the backend consistently returns HTTP 500 errors with captcha verification process failed messages, blocking access to security controls.

INFO

Published Date :

June 24, 2026, 1:16 p.m.

Last Modified :

June 25, 2026, 2:03 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-56338 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 MEDIUM 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 MEDIUM [email protected]
CVSS 4.0 MEDIUM 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 MEDIUM [email protected]
Solution
Update Capgo to version 12.128.2 or later to fix the denial of service vulnerability in the OTP endpoint.
  • Update Capgo to version 12.128.2 or later.
  • Verify email verification for two-factor authentication.
  • Ensure captcha validation is functioning correctly.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-56338 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-56338 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-56338 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-56338 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jun. 24, 2026

    Action Type Old Value New Value
    Added Reference https://github.com/Cap-go/capgo/security/advisories/GHSA-m53g-7gcj-x6f7
    Added SSVC {'id': 'CVE-2026-56338', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-24T14:58:47.357752Z'}
  • New CVE Received by [email protected]

    Jun. 24, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'Capgo', 'product': 'Capgo', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '12.128.2', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '12.128.2', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}]
    Added Description Capgo before 12.128.2 contains a denial of service vulnerability in the /auth/v1/otp endpoint that prevents email verification for two-factor authentication due to captcha validation failures. Authenticated users cannot complete 2FA enrollment as the backend consistently returns HTTP 500 errors with captcha verification process failed messages, blocking access to security controls.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
    Added CWE CWE-703
    Added Reference https://github.com/Cap-go/capgo/security/advisories/GHSA-m53g-7gcj-x6f7
    Added Reference https://www.vulncheck.com/advisories/capgo-denial-of-service-in-2fa-email-verification-via-auth-v1-otp-endpoint
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.