CVE-2026-118654 labstack CVE debrief

Who should care

Defenders responsible for Go applications using Echo should assess exposure and prioritize verification and mitigation efforts. This includes reviewing application dependencies, checking for affected versions, and implementing necessary updates or mitigations. Additionally, defenders should monitor for potential exploitation attempts and implement compensating controls if updates are not feasible.

Why it matters

CVE-2026-118654 is a route protection bypass vulnerability in Echo static file middleware. Defenders should verify exposure in Go applications, assess the need for updates or mitigations, and monitor for exploitation attempts.

• Verify exposure in Go applications using affected Echo versions
• Assess the need for updates or mitigations to prevent route protection bypass
• Implement compensating controls if updates are not feasible
• Monitor for potential exploitation attempts

Technical summary

The Echo static file middleware is vulnerable to a route protection bypass due to encoded dot-dot traversal in github.com/labstack/echo/v4 and github.com/labstack/echo/v5. Fixed versions are v4.16.0 and v5.4.0. This vulnerability can be exploited by attackers to access files and directories outside of the intended scope, potentially leading to security issues. Defenders should prioritize verifying exposure in Go applications using affected Echo versions and assess the need for updates or mitigations to prevent route protection bypass.

Defensive priority

Defenders should prioritize verifying exposure in Go applications using affected Echo versions and assess the need for updates or mitigations.

Recommended defensive actions

• Verify if Go applications using github.com/labstack/echo/v4 or github.com/labstack/echo/v5 are exposed to this vulnerability
• Assess the need for updates to v4.16.0 or v5.4.0
• Implement mitigations if updates are not feasible
• Monitor for potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check 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

Evidence notes

The vulnerability is described in the source item from osv_dev, which provides details on the affected packages and versions. However, the CVSS score and severity are not provided. The source item notes that the vulnerability affects github.com/labstack/echo/v4 and github.com/labstack/echo/v5. To verify exposure, defenders should review their applications' dependencies and check if they are using affected versions of Echo. The vulnerability's impact on the application will depend on its specific use case and configuration.

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.