CVE-2026-44267 enspirit CVE debrief

Who should care

Developers and administrators using @enspirit/elo, especially those with untrusted input, should assess exposure and prioritize remediation to prevent potential exploitation. This includes reviewing the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance, and planning vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Why it matters

CVE-2026-44267 is a high-severity vulnerability in the Elo JavaScript emitter that allows for arbitrary code execution in the host JavaScript runtime. Developers and administrators using @enspirit/elo should assess exposure and prioritize remediation to prevent potential exploitation.

• Arbitrary code execution in the host JavaScript runtime
• Sandbox escape vulnerability allowing for code execution
• Potential for exploitation via untrusted input

Technical summary

The Elo JavaScript emitter has a sandbox escape vulnerability via unfiltered `.constructor` member access, allowing an unauthenticated attacker to execute arbitrary code in the host JavaScript runtime. This vulnerability affects @enspirit/elo, particularly in scenarios with untrusted input. The vulnerability is caused by the interaction of three sites in `src/`: the `member_access` handler allows access on types `any`, `object`, or `array` without filtering the property name, the JS emitter writes `${objectExpr}.${ir.property}` verbatim into the output, and the parser accepts `constructor` (and other JS meta-property names) as an ordinary identifier.

Defensive priority

High priority for systems using @enspirit/elo, especially those with untrusted input

Recommended defensive actions

• Update @enspirit/elo to version 1.0.1 or later
• Validate and filter user input to prevent arbitrary code execution
• Implement additional security measures to protect against sandbox escapes
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• 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 source corpus provides details on the vulnerability in the Elo JavaScript emitter, including the ability for an unauthenticated attacker to execute arbitrary code in the host JavaScript runtime via unfiltered `.constructor` member access. The vulnerability is caused by the interaction of three sites in `src/`: the `member_access` handler allows access on types `any`, `object`, or `array` without filtering the property name, the JS emitter writes `${objectExpr}.${ir.property}` verbatim into the output, and the parser accepts `const

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.