Uncontrolled recursion in Pillow PDF parser causes denial of service
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 10 fixed, 9 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-674.
Summary
Pillow from 5.1.0 before 13.0.0 has uncontrolled recursion (CWE-674) in its PDF parser, which follows page-tree and trailer references without cycle tracking. An unauthenticated remote attacker can supply a crafted PDF to an application calling Image.save with PDF append enabled, causing denial of service through a RecursionError or excessive CPU and memory use. A public exploit is linked in the references.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow can exhaust resources while parsing an existing PDF during an append operation. PdfParser follows page-tree child references without cycle or duplication tracking and follows previous-trailer chains with only an exact repeated-offset guard, so deep or cyclic page trees and long chains of unique trailer offsets can exhaust the Python stack. Repeated non-cyclic /Kids references can also cause super-linear CPU and memory use. An attacker can supply such a PDF to an application that calls Image.save with PDF append enabled. This can raise an uncaught RecursionError or consume excessive CPU and memory before output is written, causing denial of service. This issue is fixed in version 13.0.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| python-pillow | Pillow | 5.1.0 to before 13.0.0 | 13.0.0 | Patch available | CNA |
| — | pillow (PyPI) | 5.1.0 to before 13.0.0 | 13.0.0 | Patch available | GHSA-p4wg-p73j-c528 |
- Pillow Vendorpython-pillow Affected 5.1.0 to before 13.0.0 Fixed in 13.0.0 Patch available CNA
- pillow (PyPI) Vendor— Affected 5.1.0 to before 13.0.0 Fixed in 13.0.0 Patch available GHSA-p4wg-p73j-c528
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:* | 5.1.0 to before 13.0.0 | Vulnerable | python-pillow |
- cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:* Versions 5.1.0 to before 13.0.0 Vulnerable ·python-pillow
Remediation
Upgrade Pillow and the PyPI package pillow to version 13.0.0. Red Hat fixes python-pillow in RHSA-2026:92639 for RHEL 8 AppStream and CRB, Satellite 6.19 in RHSA-2026:92861, and OpenShift AI 3.4 and 3.5 in RHSA-2026:92510 and RHSA-2026:94631. Red Hat lists Red Hat AI Inference Server with no fix planned and Red Hat OpenShift AI (RHOAI) with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Pillow (python-pillow) Fixed in 13.0.0
- Fix · GHSA-p4wg-p73j-c528 pillow (PyPI) Fixed in 13.0.0 Advisory →
Red Hat 13 advisories
- RHSA-2026:95655 Released 2026-11-05 · Red Hat rating CriticalSatellite 6.16 EUS security update
- Red Hat Satellite 6.16 for RHEL 8 openvox-agent-8.32.0-1.el8sat, openvox-server-8.18.0-1.el8sat, python-brotli-1.2.1-1.el8pc +11
- Red Hat Satellite 6.16 for RHEL 9 openvox-agent-8.32.0-1.el9sat, openvox-server-8.18.0-1.el9sat, python-brotli-1.2.1-1.el9pc +11
- RHSA-2026:95657 Released 2026-11-05 · Red Hat rating CriticalSatellite 6.18 security update
- Red Hat Satellite 6.18 for RHEL 9 openvox-agent-8.32.0-1.el9sat, openvox-server-8.18.0-1.el9sat, python3.12-brotli-1.2.1-1.el9pc +4
- RHSA-2026:95656 Released 2026-11-05 · Red Hat rating CriticalSatellite 6.17 security update
- Red Hat Satellite 6.17 for RHEL 9 openvox-agent-8.32.0-1.el9sat, openvox-server-8.18.0-1.el9sat, python-brotli-1.2.1-1.el9pc +9
Show 10 more Red Hat advisories
- RHSA-2026:94738 Released 2026-11-03 · Red Hat rating CriticalRed Hat AI Inference 3.5.3 (CUDA)
- Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-cuda-rhel9
- RHSA-2026:94721 Released 2026-11-03 · Red Hat rating CriticalRed Hat AI Inference Tech Preview 3.5.3 (Gaudi)
- Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-gaudi-rhel9
- RHSA-2026:94717 Released 2026-11-03 · Red Hat rating CriticalRed Hat AI Inference 3.5.3 (Spyre)
- Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-spyre-rhel9
- RHSA-2026:94715 Released 2026-11-03 · Red Hat rating CriticalRed Hat AI Inference Model Optimization Tools 3.5.3 (CUDA)
- Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/model-opt-cuda-rhel9
- RHSA-2026:94709 Released 2026-11-03 · Red Hat rating CriticalRed Hat AI Inference 3.5.3 (ROCm)
- Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-rocm-rhel9
- RHSA-2026:94702 Released 2026-11-03 · Red Hat rating CriticalRed Hat AI Inference 3.5.3 (CPU)
- Red Hat AI Inference Server 3.5 registry.redhat.io/rhaii/vllm-cpu-rhel9
- RHSA-2026:94631 Released 2026-11-03 · Red Hat rating CriticalGuideLLM 3.5.1
- Red Hat OpenShift AI 3.5 registry.redhat.io/rhai/guidellm-rhel9
- RHSA-2026:92639 Released 2026-10-29 · Red Hat rating Importantpython-pillow security update
- Red Hat Enterprise Linux AppStream (v. 8) python-pillow-5.1.1-33.el8_10, python3-pillow-5.1.1-33.el8_10
- Red Hat Enterprise Linux CRB (v. 8) python3-pillow-5.1.1-33.el8_10, python3-pillow-devel-5.1.1-33.el8_10, python3-pillow-doc-5.1.1-33.el8_10 +1
- RHSA-2026:92861 Released 2026-10-29 · Red Hat rating CriticalSatellite 6.19 security update
- Red Hat Satellite 6.19 for RHEL 9 openvox-agent-8.31.1-1.el9sat, openvox-server-8.17.0-1.el9sat, python3.12-brotli-1.2.1-1.el9pc +6
- RHSA-2026:92510 Released 2026-10-29 · Red Hat rating CriticalRHOAI 3.4.6 - Red Hat OpenShift AI
- Red Hat OpenShift AI 3.4 registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-cli-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9 +47
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Exploit Intelligence | Affected | No fix yet |
| Lightspeed Core | Affected | No fix yet |
| OpenShift Lightspeed | Affected | No fix yet |
| Red Hat AI Inference Server | Affected | No fix planned: Will not fix |
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet |
| Red Hat Lightspeed Services for OCP | Affected | No fix yet |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet |
| Red Hat Quay 3 | Affected | No fix yet |
| Red Hat AI Inference Server 3.5 | Fixed | RHSA-2026:94702, RHSA-2026:94709, RHSA-2026:94715, RHSA-2026:94717, RHSA-2026:94721, RHSA-2026:94738 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:92639 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:92639 |
| Red Hat OpenShift AI 3.4 | Fixed | RHSA-2026:92510 |
| Red Hat OpenShift AI 3.5 | Fixed | RHSA-2026:94631 |
| Red Hat Satellite 6.16 for RHEL 8 | Fixed | RHSA-2026:95655 |
| Red Hat Satellite 6.16 for RHEL 9 | Fixed | RHSA-2026:95655 |
| Red Hat Satellite 6.17 for RHEL 9 | Fixed | RHSA-2026:95656 |
| Red Hat Satellite 6.18 for RHEL 9 | Fixed | RHSA-2026:95657 |
| Red Hat Satellite 6.19 for RHEL 9 | Fixed | RHSA-2026:92861 |
Not affected: 9 products
- Red Hat AI Inference Server
- Red Hat Ansible Automation Platform 2
- Red Hat OpenShift AI (RHOAI)
- Red Hat OpenShift AI 3.4
- Red Hat Satellite 6.16 for RHEL 8
- Red Hat Satellite 6.16 for RHEL 9
- Red Hat Satellite 6.17 for RHEL 9
- Red Hat Satellite 6.18 for RHEL 9
- Red Hat Satellite 6.19 for RHEL 9
Timeline
- 2026-10-20 Threatist record created from CVE-2026-112895
- 2026-10-20 Affected versions changed · Red Hat
- 2026-10-20 CVSS score added · Red Hat
- 2026-10-20 CISA SSVC decision points changed
- 2026-10-21 Alias added: GHSA-p4wg-p73j-c528
- 2026-10-21 Fix available: PyPI/[email protected] · GHSA-p4wg-p73j-c528
- 2026-10-21 CVSS score added · GHSA-p4wg-p73j-c528
- 2026-10-21 Weakness changed · GHSA-p4wg-p73j-c528
- 2026-10-21 5 new references · GHSA-p4wg-p73j-c528
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-27 CVSS score added · NVD
- 2026-10-30 Fix available: RHSA-2026:92510 · Red Hat
- 2026-10-30 Fix available: RHSA-2026:92639 · Red Hat
- 2026-10-30 Fix available: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux CRB (v. 8), Red Hat OpenShift AI 3.4 · Red Hat
- 2026-10-30 Fix available: Red Hat Satellite 6.19 for RHEL 9 · Red Hat
- 2026-10-31 Fix available: RHSA-2026:92861 · Red Hat
- 2026-11-04 Fix available: RHSA-2026:94717 · Red Hat
- 2026-11-04 Fix available: RHSA-2026:94715 · Red Hat
- 2026-11-04 Fix available: RHSA-2026:94709 · Red Hat
- 2026-11-04 Fix available: RHSA-2026:94738 · Red Hat
- 2026-11-04 Fix available: RHSA-2026:94702 · Red Hat
- 2026-11-04 Fix available: RHSA-2026:94631 · Red Hat
- 2026-11-04 Fix available: RHSA-2026:94721 · Red Hat
- 2026-11-04 Fix available: Red Hat AI Inference Server 3.5, Red Hat OpenShift AI 3.5 · Red Hat
- 2026-11-06 Fix available: Red Hat Satellite 6.16 for RHEL 8, Red Hat Satellite 6.16 for RHEL 9, Red Hat Satellite 6.17 for RHEL 9 +1 · Red Hat
- 2026-11-06 Fix available: RHSA-2026:95656 · Red Hat
- 2026-11-06 Fix available: RHSA-2026:95655 · Red Hat
- 2026-11-06 Fix available: RHSA-2026:95657 · Red Hat
References
More python-pillow Pillow vulnerabilities
- TI-2026-76627 Out-of-bounds read in Pillow TIFF encoder ColorMap handling CVSS 4.0HIGH 8.8
- TI-2026-76625 Quadratic-time denial of service in Pillow PDF save_all CVSS 4.0HIGH 8.7
- TI-2026-76605 NULL pointer dereference in Pillow's Image.merge function CVSS 4.0HIGH 8.7
- TI-2026-76604 Out-of-bounds read in Pillow TIFF decoding leaks heap memory CVSS 4.0HIGH 8.8
- TI-2026-76602 Double free in Pillow ImagingScaleAffine on allocation failure CVSS 4.0HIGH 8.7
- TI-2026-76600 GIF seek in Pillow keeps rejected size, allowing denial of service CVSS 4.0HIGH 8.7
Sources
- CVE-2026-112895 · CVE Program
- CVE-2026-112895 · NVD
- FIRST EPSS
- GHSA-p4wg-p73j-c528 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-112895 · Red Hat security data · CC BY 4.0
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