HomeCVE Intelligence › CVE-2026-44594
CVSS 7.5 HIGH Vulnerability

CVE-2026-44594: esm.sh: Path Traversal via package.json browser field allows reading arbitrary server fil…

Summary A Local File Inclusion (LFI) vulnerability exists in the esbuild plugin's handling of the browser field in package.json. An attacker can publish an npm package that causes the server to read and return arbitrary…

7.5CVSS Score
HIGHSeverity
NOCISA KEV
VulnerabilityImpact Type

📋 Vulnerability Details

CVE IDCVE-2026-44594
Vendorgo
Affected Productgithub.com/esm-dev/esm.sh
Vulnerability TypeVulnerability
CVSS Score7.5 (HIGH)
Actively Exploited❌ No known exploitation
Patch StatusSee Vendor Advisory →
Reported ByCYBERDUDEBIVASH SENTINEL APEX Intelligence (via github_advisories)

🔬 Technical Analysis

#

Summary A Local File Inclusion (LFI) vulnerability exists in the esbuild plugin's handling of the browser field in package.json. An attacker can publish an npm package that causes the server to read and return arbitrary files from the host filesystem during the build process.

Details The vulnerable code is in the OnResolve callback of the esbuild plugin: https://github.com/esm-dev/esm.sh/blob/main/server/build.go The plugin validates that resolved file paths stay within the package working directory. However, after this check, the browser field from package.json remaps the module path to an attacker-controlled value containing ../ sequences. No validation is performed after the remapping. ```go

// Sandbox check passes for the original "./d1.txt" path if !strings.HasPref

🎯 Known Indicators of Compromise

{"type":"url","value":"https://github.com/esm-dev/esm.sh/blob/main/server/build.go","confidence_score":0.82,"first_seen":"2026-05-12","source_count":1}

📚 Advisory References

⚡ DETECTION RULES AVAILABLE

Get CVE-2026-44594 Detection Pack

Sigma rules, YARA signatures, IOC table, and SIEM queries for Splunk, Elastic, Sentinel, and Chronicle — deployable in 5 minutes.

✓ Sigma Rules ✓ YARA Pack ✓ IOC Table ✓ SIEM Queries
🛡️ Get Detection Pack → 🔌 Access via API →

🔗 Related Intelligence