CVE-2026-73647 quasarframework CVE debrief

Who should care

Defenders responsible for applications built with the Quasar Framework should assess their exposure to this vulnerability. They should prioritize updating to version 2.22.0 or later and review their applications' use of the extend() utility to ensure safe handling of user-controlled objects.

Why it matters

Defenders should care about CVE-2026-73647 because it affects the Quasar Framework's extend() utility, potentially allowing attackers to pollute the Object.prototype in the same JavaScript process. This could lead to various impacts, including logic bypass, unsafe default-option injection, and denial of service. The vulnerability is fixed in version 2.22.0, and defenders should prioritize updating and reviewing their applications' use of the extend() utility.

• Logic bypass due to prototype pollution
• Unsafe default-option injection
• Denial of service due to polluted properties
• Potential for other application-specific impacts

Technical summary

The Quasar Framework's public extend() utility, prior to version 2.22.0, had a vulnerability that allowed recursive copying of attacker-controlled object keys during deep merges without properly handling the __proto__ property. This could lead to prototype pollution, allowing attackers to write properties to Object.prototype in the same JavaScript process. Applications that passed user-controlled or partially user-controlled objects to extend() could experience logic bypass, unsafe default-option injection, denial of service, or other application-specific impacts when polluted properties were later consumed. The issue was fixed in version 2.22.0, and defenders should prioritize updating to this version or later

Defensive priority

Defenders should prioritize updating to Quasar Framework version 2.22.0 or later to mitigate this vulnerability. They should also review applications using the extend() utility to ensure they handle user-controlled objects safely and consider implementing additional validation or sanitization for objects passed to this utility.

Recommended defensive actions

• Update to Quasar Framework version 2.22.0 or later
• Review applications using the extend() utility to ensure safe handling of user-controlled objects
• Consider implementing additional validation or sanitization for objects passed to the extend() utility
• 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 about the vulnerability in the Quasar Framework's extend() utility. The issue is fixed in version 2.22.0, and several references are provided, including GitHub commits and security advisories.

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.