Pillow CVE-2026-96636

The target application must open an attacker-supplied MPO, DCX, or MIC image with Pillow AND invoke seek() to navigate to frames/pages beyond the first - that frame-seeking code path is where the MAX_IMAGE_PIXELS decompression-bomb check is bypassed. Limiting factors: single-frame opens that never call seek() are not affected; the application must process these specific multi-frame container formats; and the effect is memory/CPU exhaustion (availability) with no confidentiality or integrity impact. Exploitation requires no special non-default Pillow configuration beyond handling multi-frame images, which is common in galleries, converters, and thumbnail pipelines.

CVE-2026-96636 is a MEDIUM-severity denial-of-service issue in Pillow, where the decompression-bomb protection (the MAX_IMAGE_PIXELS guard) can be bypassed for MPO, DCX, and MIC multi-frame formats when an application calls seek() to move to additional frames/pages. No CVSS vector, CWE, EPSS score, KEV listing, or POC is present in the supplied data, so quantitative exploitation-probability signals are entirely absent and cannot be compared. The vendor (Pillow 13.0.0 release notes) classifies it as Medium, consistent with a resource-exhaustion impact rather than code execution: there is no confidentiality or integrity consequence, only availability loss via memory amplification. Real-world risk is bounded but non-trivial because Pillow is embedded in a huge number of Python web services that accept user-uploaded images and iterate frames; however, this is a DoS-only, availability-impacting bug, not a high-urgency RCE. Exploitation status is 'no public exploit identified at time of analysis' - this is NOT actively exploited and no POC is referenced. Key missing data: NVD has not yet published a CVSS vector or CWE (input shows N/A), so the authentication/attack-vector profile below is my independent assessment, not vendor-confirmed.

An attacker uploads a specially crafted MPO, DCX, or MIC image to a service that uses Pillow to process multi-frame images (e.g., thumbnailing or frame iteration). When the application calls seek() to access later frames, the normal decompression-bomb size check is skipped, so the declared frame dimensions force Pillow to allocate an enormous pixel buffer, exhausting memory and causing a denial of service. No public exploit code is identified at the time of analysis.