CVE-2026-42308 — pillow
CVE-2026-42308 is a CWE-190 vulnerability in pillow. A fix is available for pillow — see the affected versions and patch details below.
Pillow: Integer overflow when processing fonts
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42308.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
pillowReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Pillow is a Python imaging library. Prior to version 12.2.0, if a font advances for each glyph by an exceeding large amount, when Pillow keeps track of the current position, it may lead to an integer overflow. This issue has been patched in version 12.2.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pillow | all versions | 12.2.0pip install --upgrade 'pillow==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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pillow to 12.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42308 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-42308 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-42308. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
To mitigate this issue, ensure that applications utilizing the Pillow library do not process untrusted or maliciously crafted font files. Additionally, consider running applications that process image data in a sandboxed environment to limit potential impact. Reloading or restarting affected services may be required for changes to take effect.Source: Red Hat security advisory for CVE-2026-42308 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat AI Inference Server 3.3 | rhaiis/model-opt-cuda-rhel9:1778244559 | RHSA-2026:16008 |
| Red Hat AI Inference Server 3.3 | rhaiis/vllm-rocm-rhel9:1778244531 | RHSA-2026:16009 |
| Red Hat AI Inference Server 3.3 | rhaiis/vllm-cuda-rhel9:1778274666 | RHSA-2026:16030 |
| Red Hat AI Inference Server 3.4 | rhaii/vllm-spyre-rhel9:1787151840 | RHSA-2026:57387 |
Frequently Asked Questions
Is CVE-2026-42308 in your dependencies?
O3 Security finds CVE-2026-42308 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.