Which versions of bumdler-gem are malicious?

The following RubyGems versions of bumdler-gem are flagged malicious: 1.0.34790. Treat any of these as compromised.

How do I remediate bumdler-gem if I installed it?

Remove bumdler-gem 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 bumdler-gem — how do I know if it already compromised me?

If bumdler-gem 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 bumdler-gem part of a known attack campaign?

Yes — bumdler-gem is associated with the RLMA-2026-07528 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 bumdler-gem across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for bumdler-gem (version 1.0.34790).

Malicious package

bumdler-gemRubyGems

Advisory published Sep 22, 2026Updated Sep 24, 2026

bumdler-gem is a confirmed malicious RubyGems package (MAL-2026-16842) that executes malicious code on install (malicious version 1.0.34790). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bumdler-gem (RubyGems)

MAL-2026-16842

Immediate action

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

gem uninstall bumdler-gem

Malicious versions

1 flagged

1.0.34790

Indicators of compromise (SHA-256)

982e58ccc490501bf91aad06a5fcbdfd3869b42551ee7dbf5f1fa629c27827d2

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for bumdler-gem (version 1.0.34790).
If you installed it — respond
Remove bumdler-gem 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 bumdler-gem 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. bumdler-gem on RubyGems has been identified as a malicious package (version 1.0.34790 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-07528

Credits

ReversingLabs · finder

Detect & block this

O3 blocks bumdler-gem-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

Explore

All malware advisories How O3 detects malware Vulnerability database