Which versions of append-only-vec are malicious?

The following crates.io versions of append-only-vec are flagged malicious: 0.1.9. Treat any of these as compromised.

How do I remediate append-only-vec if I installed it?

append-only-vec establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

I already installed append-only-vec — how do I know if it already compromised me?

If append-only-vec 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.

How do I find append-only-vec across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for append-only-vec (version 0.1.9).

Malicious package

append-only-veccrates.io

Advisory published Aug 20, 2026Updated Aug 20, 2026

append-only-vec is a confirmed malicious crates.io package (MAL-2026-14333) that opens a backdoor for remote access (malicious version 0.1.9). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in append_only_vec (crates.io)

MAL-2026-14333

Immediate action

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

remove append-only-vec

What this malware does

append-only-vec 0.1.9 was published to crates.io from the same maintainer account (droundy) as the trojanized arrayref and internment releases, which appears to be compromised. The release adds a dependency on an attacker-controlled crate whose build script downloads and executes an architecture-specific remote binary at build time from https://23.254.165.112:9089/, passing 23.254.165.112:443 as a command-and-control address. Part of a coordinated crates.io campaign on 2026-08-20. The malicious release has been removed from crates.io; earlier append-only-vec releases are unaffected.

Malicious versions

1 flagged

0.1.9

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for append-only-vec (version 0.1.9).
If you installed it — respond
append-only-vec establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If append-only-vec 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. append-only-vec on crates.io has been identified as a malicious package (version 0.1.9 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

References

Credits

SafeDep · finder
jhobern · reporter

Detect & block this

O3 blocks append-only-vec-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database