MuJS 1.3.6 before 1.3.9 Heap Out-of-Bounds Read/Write via Array.prototype.sort
Published Oct 14, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
MuJS 1.3.6 before 1.3.9 Heap Out-of-Bounds Read/Write via Array.prototype.sort
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
MuJS 1.3.6 before 1.3.9 contains a heap out-of-bounds read and write vulnerability in Array.prototype.sort that allows attackers to corrupt memory by inflating a simple array's length. Attackers can supply JavaScript that enlarges a dense array's length and calls sort, causing Ap_sort_cmp and Ap_sort_swap to access slots past the buffer and crash the process.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- LOW
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- hackmd.io ↗
- Patch commit ↗
- Patch commit ↗
- mujs.com ↗
- codeberg.org ↗
- VulnCheck Advisory: MuJS 1.3.6 before 1.3.9 Heap Out-of-Bounds Read/Write via Array.prototype.sort ↗
Record history
Published Oct 14, 2026 · Last refreshed Nov 3, 2026