Which versions of bundlser are malicious?

The following RubyGems versions of bundlser are flagged malicious: 1.0.0, 1.0.52868. Treat any of these as compromised.

How do I remediate bundlser if I installed it?

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

If bundlser 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 bundlser part of a known attack campaign?

Yes — bundlser is associated with the RLMA-2026-07686 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 bundlser across my projects, lockfiles, and CI pipelines?

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

Malicious package

bundlserRubyGems

Advisory published Sep 22, 2026Updated Sep 24, 2026

bundlser is a confirmed malicious RubyGems package (MAL-2026-17000) that executes malicious code on install (malicious versions 1.0.0, 1.0.52868). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bundlser (RubyGems)

MAL-2026-17000

Immediate action

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

gem uninstall bundlser

Malicious versions

2 flagged

1.0.01.0.52868

Indicators of compromise (SHA-256)

26f53b8bd0b5918ed51194d2ce5baa7f7fa2ddefca8ac80eb8500f853fa50c71

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for bundlser (2 malicious versions).
If you installed it — respond
Remove bundlser 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 bundlser 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. bundlser on RubyGems has been identified as a malicious package (versions 1.0.0, 1.0.52868 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-07686

Credits

ReversingLabs · finder

Detect & block this

O3 blocks bundlser-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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