MalwarePublished 5 Aug 2026

cobrowsing-logger (npm) · Malicious Code

Affects cobrowsing-loggerSource GCVE Database

Malicious package : remove cobrowsing-logger and rotate any secrets on hosts that installed it.

Data as of 5 Aug 2026, 16:20 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-12656

What to do

Remove cobrowsing-logger from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.

Affected software

Product	Affected	Fixed in
npmcobrowsing-logger	Affected =35.7.7	Fixed in–

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Description

The npm package 'cobrowsing-logger' version 35.7.7 contains malicious code that, upon being required, downloads and executes an opaque binary from dynamically constructed hostnames. This binary is fetched without integrity verification and runs detached on the host system, potentially enabling unauthorized code execution. The package attempts to mimic benign telemetry behavior to evade detection. No official patch or remediation guidance is currently provided.

Impact

This malicious package enables arbitrary code execution on the host system of any user who installs and requires 'cobrowsing-logger' version 35.7.7. The executed binary is fetched dynamically and without verification, posing a high risk of persistent compromise, data theft, or further malware deployment. Because the binary runs detached and is not part of the package, it is difficult to detect or analyze. The opt-out branch may reduce suspicion but does not mitigate the underlying risk.

Defensive guidance

Users should immediately cease using 'cobrowsing-logger' version 35.7.7 and audit any systems where it was installed. Consider removing the package and any related dropped binaries from affected systems. Monitor for suspicious processes or network connections to the indicated domains. Check the vendor or npm advisories for updates or official fixes.

Summary

The 'cobrowsing-logger' npm package (version 35.7.7) includes a malicious module '_adapter.js' that reconstructs destination hostnames at runtime and downloads an opaque executable over HTTPS, with a DNS-TXT base64 fallback mechanism. The executable is saved to temporary directories with decoy filenames, permissioned to be executable, and then spawned detached via shell commands depending on the OS. The dropped binary is not included in the package tarball and lacks any hash or signature verification, meaning the code executed depends entirely on what the remote server serves at fetch time. An opt-out mechanism based on generic telemetry environment variables is present to simulate legitimate analytics behavior. This behavior constitutes a supply chain compromise allowing arbitrary code execution on any system requiring this package.

References

npmjs.com/package/cobrowsing-logger/v/35.7.7 (opens in a new tab)

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What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Aug 2026, 16:20 UTC

Technical details

References

Community reviews