Which versions of bumdler-lib are malicious?

The following RubyGems versions of bumdler-lib are flagged malicious: 1.0.49474. Treat any of these as compromised.

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

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

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

Yes — bumdler-lib is associated with the RLMA-2026-07529 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-lib across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for bumdler-lib (version 1.0.49474).

Malicious package

bumdler-libRubyGems

Advisory published Sep 22, 2026Updated Sep 24, 2026

bumdler-lib is a confirmed malicious RubyGems package (MAL-2026-16843) that executes malicious code on install (malicious version 1.0.49474). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bumdler-lib (RubyGems)

MAL-2026-16843

Immediate action

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

gem uninstall bumdler-lib

Malicious versions

1 flagged

1.0.49474

Indicators of compromise (SHA-256)

7e83085811d0b55645f362b57e28b8fe11f5227e829fa48f679f879acbafdde0

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for bumdler-lib (version 1.0.49474).
If you installed it — respond
Remove bumdler-lib 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-lib 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-lib on RubyGems has been identified as a malicious package (version 1.0.49474 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-07529

Credits

ReversingLabs · finder

Detect & block this

O3 blocks bumdler-lib-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

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