CVE-2026-56761 hono CVE debrief

Who should care

Defenders responsible for securing applications that use the hono library, particularly those using JSX server-side rendering, should assess exposure and implement compensating controls to prevent HTML injection attacks.

Why it matters

CVE-2026-56761 is a medium-severity vulnerability in the hono library that allows attackers to inject unintended HTML, potentially leading to security consequences. Defenders should prioritize assessing exposure and implementing compensating controls.

• Injection of arbitrary attributes or elements
• Potential for security consequences, including data tampering or unauthorized actions

Technical summary

The hono library, specifically its JSX server-side rendering feature, is vulnerable to HTML injection attacks. This occurs when an attacker uses malformed attribute names to inject unintended HTML, potentially leading to security consequences. The vulnerability has a medium CVSS score of 5.3 and affects versions prior to 4.12.14. Defenders should prioritize assessing exposure and implementing compensating controls, such as input validation and sanitization, to prevent HTML injection attacks. The CVE record and NVD entry provide details about the vulnerability, including its description, CVSS score, and affected versions.

Defensive priority

Defenders should prioritize assessing exposure and implementing compensating controls, as the vulnerability has a medium CVSS score of 5.3.

Recommended defensive actions

• Assess exposure by checking if the hono library is used in the environment and if the version is prior to 4.12.14.
• Implement compensating controls, such as input validation and sanitization, to prevent HTML injection attacks.
• Monitor for potential security incidents related to this vulnerability.
• Verify vendor remediation by checking for updates to the hono library.
• Review relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and NVD entry provide details about the vulnerability, including its description, CVSS score, and affected versions. However, the corpus does not establish versions, exploitation, impact, or remediation beyond the provided information.

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.