Python Pillow CVE-2026-59199

The vulnerable code path is reached only when an application passes a box/coordinate tuple containing values near the signed 32-bit integer limits (approximately ±2147483648) into Image.paste(), Image.crop(), or Image.alpha_composite() on a Pillow build prior to 12.3.0. The concrete precondition is that these coordinate parameters must be attacker-influenced - an app that hardcodes or tightly validates crop/paste boxes is not exploitable. Limiting factors: exploitation depends on the application surfacing raw coordinate input to these specific APIs (non-universal usage), impact is confined to availability/crash per the CVSS vector (C:N/I:N/A:H), and no user interaction or authentication is indicated (PR:N/UI:N).

The published CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N, A:H, C:N/I:N) rates this 7.5 as a network, unauthenticated availability issue - but that network reachability is conditional: exploitation requires an application to pass attacker-influenced coordinates directly into paste/crop/alpha_composite, which is not a universal usage pattern. Where coordinates are hardcoded or server-derived, remote reach effectively drops to none. No EPSS score was provided; the CVE is not listed in CISA KEV, and no weaponized POC is referenced - only the fix PR's trigger tests. Impact is scoped by NVD to availability (crash/DoS) despite the underlying primitive being a heap OOB write, so worst-case memory corruption beyond DoS is unproven from the available data. Net: a genuine, easily-triggered crash bug for exposed image-processing services, but 'critical-priority' status hinges on whether your app actually exposes coordinate parameters - verify usage rather than treating AV:N as automatically remotely reachable.

A web service lets users crop or composite uploaded images by submitting box coordinates via an API. An attacker submits a request with coordinates near the 32-bit limits (e.g. left=2147483647, right=-2147483648); the size subtraction overflows in libImaging and Pillow performs a heap out-of-bounds write, crashing the worker process and denying service. No authentication is indicated by the CVSS vector, and no public exploit code is referenced - only the fix PR's trigger inputs.