CVE-2026-89059 Red Hat CVE debrief

Who should care

Defenders responsible for RESTEasy deployments should assess exposure and prioritize verification and patching to prevent potential denial-of-service attacks. This includes reviewing and updating inventory of affected systems, monitoring for potential denial-of-service attacks, and planning vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Why it matters

CVE-2026-89059 is a denial-of-service vulnerability in RESTEasy's IIOImageProvider that allows a remote, unauthenticated attacker to exhaust the JVM heap by sending a crafted image with enormous dimensions. Defenders responsible for RESTEasy deployments should assess exposure and prioritize verification and patching to prevent potential denial-of-service attacks. The vulnerability's impact is limited to availability, with no reported exploitation or data breaches. However, the lack of information on affected versions and remediation requires defenders to verify and apply patches or mitigations.

• Denial of service through JVM heap exhaustion
• Potential disruption to critical systems and services
• Need for verification and patching of affected systems
• Possible impact on system availability and reliability

Technical summary

The IIOImageProvider in RESTEasy decodes attacker-supplied image request bodies without enforcing limits on declared image dimensions or pixel count, allowing a remote, unauthenticated attacker to trigger a large memory allocation and exhaust the JVM heap. This vulnerability affects RESTEasy deployments and requires defenders to assess exposure and prioritize verification and patching to prevent potential denial-of-service attacks. The vulnerability's impact is limited to availability, with no reported exploitation or data breaches.

Defensive priority

Defenders should prioritize verifying and applying patches or mitigations to prevent potential denial-of-service attacks.

Recommended defensive actions

• Verify and apply patches or mitigations for RESTEasy IIOImageProvider
• Monitor for potential denial-of-service attacks
• Review and update inventory of affected systems
• 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 limited. Defenders should verify and apply patches or mitigations to prevent potential denial-of-service attacks. The lack of information on affected versions and remediation requires defenders to review and update inventory of affected systems and monitor for potential denial-of-service attacks.

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.