Which versions of biundler-rb are malicious?

The following RubyGems versions of biundler-rb are flagged malicious: 1.0.45042. Treat any of these as compromised.

How do I remediate biundler-rb if I installed it?

Remove biundler-rb 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 biundler-rb — how do I know if it already compromised me?

If biundler-rb 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 biundler-rb part of a known attack campaign?

Yes — biundler-rb is associated with the RLMA-2026-07321 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 biundler-rb across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for biundler-rb (version 1.0.45042).

Malicious package

biundler-rbRubyGems

Advisory published Sep 22, 2026Updated Sep 24, 2026

biundler-rb is a confirmed malicious RubyGems package (MAL-2026-16657) that executes malicious code on install (malicious version 1.0.45042). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in biundler-rb (RubyGems)

MAL-2026-16657

Immediate action

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

gem uninstall biundler-rb

Malicious versions

1 flagged

1.0.45042

Indicators of compromise (SHA-256)

5727f47b96c9a64b458f574d05b0dbef796fc9a9862a30e80a07f900441901c0

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for biundler-rb (version 1.0.45042).
If you installed it — respond
Remove biundler-rb 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 biundler-rb 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. biundler-rb on RubyGems has been identified as a malicious package (version 1.0.45042 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-07321

Credits

ReversingLabs · finder

Detect & block this

O3 blocks biundler-rb-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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