LWA-2026-4054 MAL-2026-5539 ↗ confirmed malware

mermaid-v11@9999.0.0

Malicious code in mermaid-v11 (npm)

T1195.002 · Compromise Software Supply ChainT1059.007 · JavaScriptT1082 · System Information DiscoveryT1071.001 · Web ProtocolsT1071.004 · DNST1041 · Exfiltration Over C2 Channel

Analysis

mermaid-v11 combosquats the real mermaid diagramming library. The package contains only a package.json with a preinstall hook that collects hostname and username via os.hostname() and os.userInfo().username, then exfiltrates them to d8ks495t5p5ut2enft8041g7fusnfsy5e[.]oast[.]site via both an HTTPS GET and a DNS lookup (using the subdomain as a side channel). Version 9999.0.0 and the absence of any real library code confirm a combosquat reconnaissance beacon.

analyzed by
Leitwacht
first seen
Jun 11, 2026, 12:35 AM
analyzed
Jun 11, 2026, 12:35 AM

Related advisories

browse all confirmed advisories →

Independently detected by the Leitwacht supply-chain probe. IOCs are defanged. Published CC0. Think this is a mistake? See the dispute policy.