CVE-2026-112894
8.7HighPublished 19 Oct 2026 · NVD status: Received · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Impact
- High impact on availability
- Weakness
- CWE-407
Impact
Remote unauthenticated attackers can cause a denial of service by exhausting CPU on servers converting images to PDFs. They only need to upload a crafted multi-frame image, such as an APNG with an inflated frame count.
Root cause
PdfParser.next_object_id() repeatedly scans and rebuilds all previously allocated PDF object identifiers for each frame, causing quadratic runtime when saving multipage PDFs with save_all.
Affected systems
Pillow 5.1.0 through 12.x (fixed in 13.0.0)
CVSS v4.0 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Fix & remediation
Upgrade Pillow to version 13.0.0 or later. If you cannot upgrade immediately, reject or restrict image uploads with large frame counts before converting them to PDF.
$ pip install --upgrade 'Pillow>=13.0.0'AI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD description
Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow takes quadratic time to reserve PDF object identifiers when saving many frames with save_all enabled. PdfParser.next_object_id() repeatedly rebuilds and scans all previously reserved identifiers for every object. An attacker can supply a multi-frame image, including a small APNG with a large declared frame count, to an application that converts it to a multipage PDF. This can consume excessive CPU and deny service. This issue is fixed in version 13.0.0.