---
id: "MAL-2026-16203"
kind: "package"
aliases: ["MAL-2026-16203"]
title: "Malicious code in faiss-cpu-avx512 (PyPI)"
severity: "critical"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "faiss-cpu-avx512", "fixed": [], "affected": "= 1.9.0; = 1.9.1; = 1.9.2; = 1.9.3; = 1.9.4; = 1.9.5; = 1.9.6; = 1.9.7", "ecosystem": "pypi"}]
ecosystems: ["pypi"]
tags: ["malicious", "package"]
not_affected_if: []
published_at: "2026-09-14T00:00:00+00:00"
first_seen_at: "2026-10-26T20:51:57+00:00"
updated_at: "2026-10-26T21:10:31+00:00"
sources: [{"source": "osv-malicious", "url": "https://osv.dev/vulnerability/MAL-2026-16203", "first_seen_at": "2026-10-26T20:51:57+00:00"}]
---

# Malicious code in faiss-cpu-avx512 (PyPI)

## Affected

- pypi:faiss-cpu-avx512 affected = 1.9.0; = 1.9.1; = 1.9.2; = 1.9.3; = 1.9.4; = 1.9.5; = 1.9.6; = 1.9.7 fixed ?

## Timeline

- 2026-10-26T20:51:57+00:00 osv-malicious https://osv.dev/vulnerability/MAL-2026-16203

## From the sources

faiss-cpu-avx512@1.9.0 through 1.9.7 on PyPI impersonates faiss-cpu and ships no FAISS code: faiss_cpu_avx512/__init__.py _fetch_native() downloads an xz-compressed binary from https://files.catbox.moe/ (ffoa50.xz in 1.9.0 to 1.9.3, 0oreqo.xz in 1.9.4, vwfr94.xz in 1.9.5, 3l3x0v.xz in 1.9.6, weu5u2.xz in 1.9.7), writes it to ~/.cache/faiss_cpu_avx512/bin/indexwrm with mode 0755 and runs it through subprocess.Popen(start_new_session=True), restarting it every 5 seconds for the life of the process. It triggers on a call to warmup() or start(); nothing runs on install or import, and the ARTIFACT_SHA256 constant is the string PENDING_BUILD so the advertised checksum check never executes. 1.9.0 to 1.9.3 reach the download only on hosts whose nvidia-smi reports compute capability 9 or 10; 1.9.4 onward download on every host and start one worker per GPU, and the code comments describe the binary as carrying a baked-in pool, wallet and relay and renaming its process to a vllm serve command line. We read all eight wheels between 2026-09-11 and 2026-09-14 and did not retrieve or run the binary.

---

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