CVE-2026-56073: Cap-go - OTP Bypass via Response Manipulation in Email Verification

Severity: critical (CVSS 9.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-19 · updated 2026-10-25
Weakness: CWE-345

Description

Cap-go before 12.128.2 contains an authentication bypass vulnerability in OTP verification that allows attackers to bypass email verification by modifying server responses. Attackers can intercept OTP verification requests and manipulate HTTP responses to falsely mark verification successful, enabling unauthorized 2FA enablement and account takeover.

Affected products

Cap-go capgo: before 12.128.2 — fixed in 12.128.2

How to fix

Upgrade to a fixed version: Cap-go capgo 12.128.2. Check the vendor advisory for mitigations.

References

https://github.com/Cap-go/capgo/security/advisories/GHSA-x2gq-85v8-j9v4
https://www.vulncheck.com/advisories/cap-go-otp-bypass-via-response-manipulation-in-email-verification
https://github.com/Cap-go/capgo/security/advisories/GHSA-x2gq-85v8-j9v4

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