🛡️ MAL-2026-12656 — cobrowsing-logger

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Malicious code in cobrowsing-logger (npm)

Source: amazon-inspector

index.js unconditionally requires _adapter.js on load. _adapter.js reconstructs destination hostnames from string-split fragments (assembling oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev, and sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru at runtime), platform-branches on the host OS, downloads an opaque executable over HTTPS with a DNS-TXT base64 fallback under the *.dl.wel1.ru zone, writes it to /tmp or %TEMP% under a decoy filename (.cache_<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe. An opt-out branch is gated on generic-telemetry environment variables to mimic benign analytics behavior. The dropped binary is not shipped in the tarball and is not verified by hash or signature; whatever the operator of the Workers hosts / DNS-TXT channel serves at fetch time runs detached on the installer's machine on every require('cobrowsing-logger').

Affected software

MAL-2026-12656 is recorded against 1 package.

  • cobrowsing-logger

Timeline and source

Published on 5 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

www.npmjs.com (Package)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector N/A
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-08-05
Updated 2026-08-12
Modified 2026-08-05
Fix URL N/A

Affected Packages

Software From version Fixed in
cobrowsing-logger — —

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