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TI-2026-79005 Aliases CVE-2026-96640GHSA-mrfp-p49p-3hf2

Resource exhaustion in Pillow PDF append via malformed page tree

Priority HIGH 75CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
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-400.

Summary

Pillow from 5.1.0 before 13.0.0 is affected. Its PDF parser does not track duplicate references in a page tree, so a shared child page node is expanded as distinct pages (CWE-400). A remote unauthenticated attacker who supplies a compact malformed PDF to be appended can create exponentially many page references and consume disproportionate CPU.

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, PdfParser.linearize_page_tree() in src/PIL/PdfParser.py treats a PDF /Pages graph as a tree without tracking duplicate indirect references. When Image.save(..., format="PDF", append=True) processes an attacker-controlled existing PDF whose /Kids arrays repeatedly reference the same child /Pages node, Pillow expands the shared subtree as distinct pages. A compact malformed PDF can therefore create exponentially many page references and consume disproportionate CPU before the append completes. This issue is fixed in version 13.0.0.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00604 49th percentileScored 2026-11-07
Fix Partial Pillow (python-pillow): 13.0.0Pillow (PyPI): 13.0.0Red Hat: 13 advisoriesRed Hat: 10 fixed, 9 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
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

VendorProductAffected versionsFixed inStatusSource
python-pillowPillow5.1.0 to before 13.0.013.0.0Patch availableCNA
—Pillow (PyPI)5.1.0 to before 13.0.013.0.0Patch availableGHSA-mrfp-p49p-3hf2
  • 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-mrfp-p49p-3hf2

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*5.1.0 to before 13.0.0Vulnerablepython-pillow
  • cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:* Versions 5.1.0 to before 13.0.0 Vulnerable ·python-pillow

Remediation

Upgrade Pillow to 13.0.0 on PyPI and python-pillow. Red Hat fixes it in RHSA-2026:92639, RHSA-2026:92510, RHSA-2026:92861, RHSA-2026:95655, RHSA-2026:95656, RHSA-2026:95657, RHSA-2026:94631, RHSA-2026:94702, RHSA-2026:94709, RHSA-2026:94715, RHSA-2026:94717, RHSA-2026:94721 and RHSA-2026:94738. Red Hat lists Red Hat Enterprise Linux AI 3, Red Hat Ansible Automation Platform 2 and Red Hat Quay 3 as affected 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-mrfp-p49p-3hf2 Pillow (PyPI) Fixed in 13.0.0 Advisory →

Red Hat 13 advisories

  • RHSA-2026:95655 Released 2026-11-05 · Red Hat rating Critical
    Satellite 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 Critical
    Satellite 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 Critical
    Satellite 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 Critical
    Red 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 Critical
    Red 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 Critical
    Red 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 Critical
    Red 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 Critical
    Red 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 Critical
    Red 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 Critical
    GuideLLM 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 Important
    python-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 Critical
    Satellite 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 Critical
    RHOAI 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 →

ProductStatusPlan or fix
Exploit IntelligenceAffectedNo fix yet
Lightspeed CoreAffectedNo fix yet
OpenShift LightspeedAffectedNo fix yet
Red Hat AI Inference ServerAffectedNo fix planned: Will not fix
Red Hat Ansible Automation Platform 2AffectedNo fix yet
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet
Red Hat Lightspeed Services for OCPAffectedNo fix yet
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet
Red Hat Quay 3AffectedNo fix yet
Red Hat AI Inference Server 3.5Fixed 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 3.4Fixed RHSA-2026:92510
Red Hat OpenShift AI 3.5Fixed RHSA-2026:94631
Red Hat Satellite 6.16 for RHEL 8Fixed RHSA-2026:95655
Red Hat Satellite 6.16 for RHEL 9Fixed RHSA-2026:95655
Red Hat Satellite 6.17 for RHEL 9Fixed RHSA-2026:95656
Red Hat Satellite 6.18 for RHEL 9Fixed RHSA-2026:95657
Red Hat Satellite 6.19 for RHEL 9Fixed RHSA-2026:92861
Not affected: 8 products
  • 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

  1. 2026-10-21 Threatist record created from CVE-2026-96640
  2. 2026-10-22 Alias added: GHSA-mrfp-p49p-3hf2
  3. 2026-10-22 Fix available: PyPI/[email protected] · GHSA-mrfp-p49p-3hf2
  4. 2026-10-22 CVSS score added · GHSA-mrfp-p49p-3hf2
  5. 2026-10-22 Weakness changed · GHSA-mrfp-p49p-3hf2
  6. 2026-10-22 6 new references · GHSA-mrfp-p49p-3hf2
  7. 2026-10-23 Affected versions changed · Red Hat
  8. 2026-10-23 CVSS score added · Red Hat
  9. 2026-10-23 Priority changed: MEDIUM → LOW
  10. 2026-10-24 Affected versions changed · Red Hat
  11. 2026-10-27 CVSS score added · NVD
  12. 2026-10-28 CISA SSVC decision points changed
  13. 2026-10-28 Priority changed: LOW → HIGH
  14. 2026-10-30 Fix available: RHSA-2026:92510 · Red Hat
  15. 2026-10-30 Fix available: RHSA-2026:92639 · Red Hat
  16. 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
  17. 2026-10-30 Fix available: Red Hat Satellite 6.19 for RHEL 9 · Red Hat
  18. 2026-10-31 Fix available: RHSA-2026:92861 · Red Hat
  19. 2026-11-04 Fix available: RHSA-2026:94717 · Red Hat
  20. 2026-11-04 Fix available: RHSA-2026:94715 · Red Hat
  21. 2026-11-04 Fix available: RHSA-2026:94709 · Red Hat
  22. 2026-11-04 Fix available: RHSA-2026:94738 · Red Hat
  23. 2026-11-04 Fix available: RHSA-2026:94702 · Red Hat
  24. 2026-11-04 Fix available: RHSA-2026:94631 · Red Hat
  25. 2026-11-04 Fix available: RHSA-2026:94721 · Red Hat
  26. 2026-11-04 Fix available: Red Hat AI Inference Server 3.5, Red Hat OpenShift AI 3.5 · Red Hat
  27. 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
  28. 2026-11-06 Fix available: RHSA-2026:95656 · Red Hat
  29. 2026-11-06 Fix available: RHSA-2026:95655 · Red Hat
  30. 2026-11-06 Fix available: RHSA-2026:95657 · Red Hat

References

Patch 1

Advisory 2

Other 3

  • 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
See all 110 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences