CVE-2026-56764 Hono CVE debrief

Who should care

Developers and administrators responsible for Hono deployments should assess their exposure and prioritize patching or mitigating this vulnerability. This includes reviewing authentication configurations, verifying Hono versions, and applying patches or mitigations as available. Additionally, security teams and vulnerability management teams should be aware of the potential impact and ensure proper monitoring and incident response planning.

Why it matters

CVE-2026-56764 is a timing attack vulnerability in Hono's basicAuth and bearerAuth middlewares that allows attackers to infer valid credentials. Defenders should verify Hono versions, apply patches, and review authentication configurations.

• Credential inference through timing measurements may lead to unauthorized access.
• Requires verification of Hono version and potential patching or mitigation.
• May necessitate review and update of authentication configurations.

Technical summary

The vulnerability is caused by non-constant-time string comparison in the timingSafeEqual function used in Hono's basicAuth and bearerAuth middlewares. This allows attackers to exploit early termination of string equality checks to infer valid credentials through precise timing measurements. The issue arises in Hono versions prior to 4.11.10 and can be mitigated by upgrading to a patched version or applying compensating controls. Defenders should assess their exposure and prioritize patching or mitigating this vulnerability.

Defensive priority

Defenders should prioritize verifying the version of Hono in use and applying patches or mitigations as available. This vulnerability requires attention from developers and administrators responsible for Hono deployments.

Recommended defensive actions

• Verify the version of Hono in use and apply patches or mitigations as available.
• Review and update authentication and authorization configurations for Hono deployments.
• Monitor Hono deployments for potential exploitation attempts.
• Perform vulnerability scanning to identify exposed Hono deployments.
• Implement additional logging and monitoring for authentication events.
• Review access controls and ensure proper segregation of duties.
• Conduct regular security audits to detect potential misconfigurations.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description and CVSS score. However, the exact scope of affected versions and deployments is not specified, requiring further verification.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.