CVE-2026-40192
CVE-2026-40192 is a Uncontrolled Resource Consumption vulnerability in pillow. O3 Security confirms whether CVE-2026-40192 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Pillow is vulnerable to a FITS GZIP decompression bomb
Blast Radius
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Description
Pillow is a Python imaging library. Versions 10.3.0 through 12.1.1 did not limit the amount of GZIP-compressed data read when decoding a FITS image, making them vulnerable to decompression bomb attacks. A specially crafted FITS file could cause unbounded memory consumption, leading to denial of service (OOM crash or severe performance degradation). If users are unable to immediately upgrade, they should only open specific image formats, excluding FITS, as a workaround.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pillow | ≥ 10.3.0&&< 12.2.0 | 12.2.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pillow. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update pillow to 12.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40192 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-40192 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-40192. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-40192 in your dependencies?
O3 detects CVE-2026-40192 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.