HighCVE-2026-112399

Pillow: APNG background disposal allocates full canvas before decompression bomb check (CVE-2026-112399)

Published 19.10.2026Last modified 28.10.2026Sources: Red Hat, OSV, CVE.org, Hersteller

Public exploit

What is affected, what to do

A flaw was found in Pillow. A remote attacker can trigger a Denial of Service (DoS) by providing a specially crafted Animated Portable Network Graphics (APNG) image.

An exploit is publicly available. Update pillow to version 13.0.0, Pillow to version 13.0.0.

Affected: Python-pillow Pillow gte 8.1.0, < 13.0.0..*

Not sure whether and how you are affected? Ask a question about this vulnerability

Metrics

8.7

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: Vendor (CNA), CVSS v4

7.5

CVSS v3

Severity High on the scale from 0 to 10.

Source: Red Hat, OSV, CVE.org, Hersteller

0.5 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 44.7

Show all metrics

Severity: High
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 89.48 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: PoC (publicly reported)
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 8.7 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 7.5
CVSS v4 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 8.7
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 0.5 %; Low — model estimates < 1% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 44.7; High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: —
Published: 19.10.2026
CISA assessment (SSVC): Exploitation: proof of concept · automatable · Technical impact: partial; Source: CISA Vulnrichment, as of 28 October 2026
CWE CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect. Read in glossary: CWE-789

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

A flaw was found in Pillow. A remote attacker can trigger a Denial of Service (DoS) by providing a specially crafted Animated Portable Network Graphics (APNG) image. Pillow allocates memory for the full canvas dimensions before validating safety size limits during initial file opening. Processing such an image can exhaust available system memory and cause the application to crash.

Source: redhat_csaf, OSV (Open Source Vulnerabilities), NVD (NIST), GitHub Security Advisories, cvelistv5

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
python-pillow	Pillow	`≥ 8.1.0, < 13.0.0`	—
python	pillow	`8.1.0 – < 13.0.0`	`13.0.0`
pip	Pillow	`>= 8.1.0, < 13.0.0`	`13.0.0`
pypi	pillow	`8.3.1` `8.3.0` `9.2.0` `12.2.0` `10.2.0` `10.4.0` `8.1.2` `9.5.0` `8.3.2` `12.1.1` `11.0.0` `11.3.0` `9.0.1` `12.1.0` `10.0.0` `8.2.0` `9.3.0` `12.0.0` `8.1.1` `11.1.0` `10.0.1` `8.1.0` `9.4.0` `11.2.1` `9.0.0` `8.4.0` `9.1.0` `12.3.0` `10.3.0` `9.1.1` `10.1.0`	— — — — — — — — — — — — — — — — — — — — — `13.0.0` — — — — — — — — —

Distribution and container packages (1)

Downstream packages (e.g. Bitnami, Debian, Ubuntu, Red Hat). Versions refer to the distribution, not the vendor.

Distribution and container packages
		Affected versions	Fixed in
bitnami	pillow	`8.1.0`	`13.0.0`

Vendors and products

Weakness classes (CWE)

CWE-789Memory Allocation with Excessive Size Value
Variant
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
Entry at MITRE CWE-789

Public exploit references

Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

Public exploit references

Reference tagged as exploit	github.com (opens in a new tab)	PoC (publicly reported)reported, not verified	—

References & sources

github.compython-pillow/Pillow/commit/f1acfc54c53502948d0d14121872061df93…x_refsource_MISC, web, Patch, fix
github.compython-pillow/Pillow/releases/tag/13.0.0x_refsource_MISC, web, Release notes, article
github.compython-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9x_refsource_CONFIRM, web, Exploit, Mitigation, Patch, Vendor advisory, advisory
NVD (NIST)vuln/detail/CVE-2026-112399advisory, web
github.compython-pillow/Pillowpackage

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

28.10.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: proof of concept, automatable: yes

New references:

https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9

Show 2 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Reference	added	—	https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9
SSVC assessment	added	—	{"id":"CVE-2026-112399","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-28T15:21:08.274556Z"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

27.10.2026Initial analysis by NVDNVD

Newly listed as affected:

Python Software Foundation Pillow (8.1.0 – before 13.0.0)

CVSS V3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

New references:

Show 5 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
CVSS	added	—	AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Product configuration	added	—	OR cpe:2.3:a:python:pillow::::::::* versions from (including) 8.1.0 up to (excluding) 13.0.0
Reference type	added	—	GitHub, Inc.: https://github.com/python-pillow/Pillow/commit/f1acfc54c53502948d0d14121872061df931db48 Types: Patch
Reference type	added	—	GitHub, Inc.: https://github.com/python-pillow/Pillow/releases/tag/13.0.0 Types: Release Notes
Reference type	added	—	GitHub, Inc.: https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9 Types: Exploit, Mitigation, Patch, Vendor Advisory

Source identifier: nvd@nist.gov

19.10.2026ReceivedGitHub

CVSS V4.0: AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Weakness type: CWE-789

Description added or changed

New references:

Show 7 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Description	added	—	Pillow is a Python imaging library. From 8.1.0 until 13.0.0, Pillow can allocate an APNG disposal background at the full canvas size before applying the decompression-bomb check. A crafted APNG with a small first frame, a very large declared canvas, and background disposal or first-frame OP_PREVIOUS reaches PngImageFile._seek while Image.open() positions frame zero. The full-canvas allocation occurs inside Image.open() without requiring pixel loading or frame iteration. This can exhaust memory and deny service. This issue is fixed in version 13.0.0.
CVSS	added	—	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
Weakness type (CWE)	added	—	CWE-789
Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/112xxx/CVE-2026-112399.json">CVE-2026-112399</a>
Reference	added	—	https://github.com/python-pillow/Pillow/commit/f1acfc54c53502948d0d14121872061df931db48
Reference	added	—	https://github.com/python-pillow/Pillow/releases/tag/13.0.0
Reference	added	—	https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9

Source identifier: security-advisories@github.com

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