Which versions of bundsler are malicious?

The following RubyGems versions of bundsler are flagged malicious: 1.0.0, 1.0.38469. Treat any of these as compromised.

How do I remediate bundsler if I installed it?

Remove bundsler 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 bundsler — how do I know if it already compromised me?

If bundsler 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 bundsler part of a known attack campaign?

Yes — bundsler is associated with the RLMA-2026-07704 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 bundsler across my projects, lockfiles, and CI pipelines?

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

Malicious package

bundslerRubyGems

Advisory published Sep 22, 2026Updated Sep 24, 2026

bundsler is a confirmed malicious RubyGems package (MAL-2026-17018) that executes malicious code on install (malicious versions 1.0.0, 1.0.38469). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bundsler (RubyGems)

MAL-2026-17018

Immediate action

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

gem uninstall bundsler

Malicious versions

2 flagged

1.0.01.0.38469

Indicators of compromise (SHA-256)

1f47a97873ef8be1092f8c6be6db4dee9f81b559f117ef3f0b284f9fcbf06383

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for bundsler (2 malicious versions).
If you installed it — respond
Remove bundsler 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 bundsler 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. bundsler on RubyGems has been identified as a malicious package (versions 1.0.0, 1.0.38469 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-07704

Credits

ReversingLabs · finder

Detect & block this

O3 blocks bundsler-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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