CVE-2026-93493 Red Hat CVE debrief

Who should care

Defenders responsible for configuring and monitoring Netty applications, particularly those using the `netty-handler-ssl-ocsp` component, should assess their exposure and verify certificate validation mechanisms.

Why it matters

CVE-2026-93493 is a medium-severity vulnerability in Netty's `netty-handler-ssl-ocsp` component that can cause OCSP validation to be skipped, potentially bypassing security controls. Defenders should prioritize verifying the presence of the `nextUpdate` field in OCSP responses and ensuring proper certificate validation.

• Potential bypass of security controls where certificate validation is expected
• Verification of OCSP response validation mechanisms required
• Need to review and update security controls to account for potential bypass

Technical summary

A remote attacker can exploit a flaw in Netty's `netty-handler-ssl-ocsp` component by providing an Online Certificate Status Protocol (OCSP) response that omits the optional `nextUpdate` field. This omission causes the OCSP validation to be silently skipped, leading to applications proceeding with an unvalidated certificate. The vulnerability affects Netty's `netty-handler-ssl-ocsp` component, and defenders should prioritize verifying the presence of the `nextUpdate` field in OCSP responses and ensuring proper certificate validation.

Defensive priority

Defenders should prioritize verifying the presence of the `nextUpdate` field in OCSP responses and ensuring proper certificate validation.

Recommended defensive actions

• Verify the presence of the `nextUpdate` field in OCSP responses
• Ensure proper certificate validation in applications
• Review and update security controls to account for potential bypass
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but additional information on affected versions and remediation is needed. The vulnerability affects Netty's `netty-handler-ssl-ocsp` component, and defenders should verify the presence of the `nextUpdate` field in OCSP responses and ensure proper certificate validation. The source details are limited, and explicit evidence-limit language and defensive verification tasks are required.

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.