Pillow EUVD-2026-104655

Exploitation requires an application that calls Pillow's FreeType text rendering (ImageFont/ImageDraw) with a nonzero stroke_width AND loads an attacker-controlled font from untrusted bytes; the attacker must supply a malformed font that forces the FT_Load_Glyph failure path with an active stroker. Limiting factors: the vulnerable code path is only reached when stroking is enabled (stroke_width > 0) - applications that render text without stroking, or that only use trusted/bundled fonts, are not exposed. This corresponds to the AT:P (Attack Requirements: Present) bit in the CVSS 4.0 vector. Affected Pillow versions are 10.0.0 up to (not including) 13.0.0; no authentication or user interaction is required on the application side per PR:N/UI:N.

This is a memory-safety flaw (CWE-457, use of uninitialized/stale variable) in Pillow's FreeType text rendering path, triggered when FT_Load_Glyph fails and cleanup calls FT_Done_Glyph on an invalid FT_Glyph pointer. The provided CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N) scores 8.2 with VA:H but VC:N/VI:N - i.e. the vendor rates impact as availability-only (crash/DoS), not confidentiality or integrity, despite the description's mention that it 'can corrupt memory.' This is a notable signal to weigh: although freeing an invalid pointer is theoretically exploitable for code execution, the CVSS vector claims no integrity/confidentiality impact, so treat RCE as unconfirmed and DoS as the realistic outcome. The AT:P (Attack Requirements: Present) bit is critical - exploitation is NOT universal: the target application must actually draw text with a nonzero stroke width using attacker-controlled (untrusted) font bytes. No EPSS score, CISA KEV listing, or POC was provided in the input, so there is no evidence of active exploitation or public exploit code. Net: this is a genuine but conditional defect - high CVSS driven by network reach and no-auth, but the AT:P precondition and availability-only impact place it below the tier of a wormable, default-config RCE. Prioritize for applications that render user-supplied fonts with stroking (e.g. image/text-generation services); deprioritize where fonts are trusted or stroking is unused.

An application (e.g. a web service generating images or captchas) uses Pillow to draw text with a nonzero stroke width and loads a font from untrusted input. An attacker uploads a malformed/corrupt font file that forces FT_Load_Glyph to fail, driving the cleanup path to call FT_Done_Glyph on an uninitialized or stale glyph pointer, crashing the worker or potentially corrupting heap memory. No public exploit code was identified in the provided data.