Which versions of blundler are malicious?

The following RubyGems versions of blundler are flagged malicious: 1.0.0, 1.0.6302. Treat any of these as compromised.

How do I remediate blundler if I installed it?

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

If blundler 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 blundler part of a known attack campaign?

Yes — blundler is associated with the RLMA-2026-07394 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 blundler across my projects, lockfiles, and CI pipelines?

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

Malicious package

blundlerRubyGems

Advisory published Sep 22, 2026Updated Sep 24, 2026

blundler is a confirmed malicious RubyGems package (MAL-2026-16726) that executes malicious code on install (malicious versions 1.0.0, 1.0.6302). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in blundler (RubyGems)

MAL-2026-16726

Immediate action

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

gem uninstall blundler

Malicious versions

2 flagged

1.0.01.0.6302

Indicators of compromise (SHA-256)

4d580c3b6688dd490d3366cbdaed0a0c9ae1a7b059e7fe8051d0d7083b3f86b7

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for blundler (2 malicious versions).
If you installed it — respond
Remove blundler 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 blundler 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. blundler on RubyGems has been identified as a malicious package (versions 1.0.0, 1.0.6302 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-07394

Credits

ReversingLabs · finder

Detect & block this

O3 blocks blundler-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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