Which versions of bsundler are malicious?

The following RubyGems versions of bsundler are flagged malicious: 1.0.0, 1.0.87539. Treat any of these as compromised.

How do I remediate bsundler if I installed it?

Remove bsundler from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

I already installed bsundler — how do I know if it already compromised me?

If bsundler was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Is bsundler part of a known attack campaign?

Yes — bsundler is associated with the RLMA-2026-07447 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find bsundler across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for bsundler (2 malicious versions).

Malicious package

bsundlerRubyGems

Advisory published Sep 22, 2026Updated Sep 24, 2026

bsundler is a confirmed malicious RubyGems package (MAL-2026-16762) that executes malicious code on install (malicious versions 1.0.0, 1.0.87539). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bsundler (RubyGems)

MAL-2026-16762

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

gem uninstall bsundler

Malicious versions

2 flagged

1.0.01.0.87539

Indicators of compromise (SHA-256)

24a733dbcd87977abaeae368ea28ac35ca5f306c2a2708252e1af50424f27a39

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for bsundler (2 malicious versions).
If you installed it — respond
Remove bsundler from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If bsundler was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. bsundler on RubyGems has been identified as a malicious package (versions 1.0.0, 1.0.87539 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-07447

Credits

ReversingLabs · finder

Detect & block this

O3 blocks bsundler-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.

Malware detection Runtime egress monitoring

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