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Quadratic GIF comment handling in Pillow allows denial of service

Priority LOW 37CWE-407Published · Updated

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 · Low
Fix status
Partial Red Hat: 1 fixed, 11 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-407.

Summary

Pillow from 5.4.0 before 13.0.0 is affected. Pillow performs quadratic copying when it parses GIF comment extensions in GifImageFile._seek(), a weakness covered by CWE-407. An unauthenticated remote attacker can send a small GIF with many comment extensions to any application that opens it, consuming CPU and denying service during Image.open(). The references link an exploit.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

Pillow is a Python imaging library. From 5.4.0 until 13.0.0, Pillow performs quadratic copying while parsing GIF comments. GifImageFile._seek() repeatedly appends immutable bytes for comment sub-blocks and multiple comment extensions, and frame zero is parsed during Image.open(). An attacker can submit a small-dimension GIF containing many comment extensions to any application that opens the file. This can consume excessive CPU and deny service before the application can inspect the image. This issue is fixed in version 13.0.0.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00649 51st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Pillow (python-pillow): 13.0.0Pillow (PyPI): 13.0.0Red Hat: 6 advisoriesRed Hat: 1 fixed, 11 without a fix

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

VendorProductAffected versionsFixed inStatusSource
python-pillowPillow5.4.0 to before 13.0.013.0.0Patch availableCNA
—Pillow (PyPI)5.4.0 to before 13.0.013.0.0Patch availableGHSA-74r2-7ff9-mjj2
  • Pillow Vendorpython-pillow Affected 5.4.0 to before 13.0.0 Fixed in 13.0.0 Patch available CNA
  • Pillow (PyPI) Vendor— Affected 5.4.0 to before 13.0.0 Fixed in 13.0.0 Patch available GHSA-74r2-7ff9-mjj2

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*5.4.0 to before 13.0.0Vulnerablepython-pillow
  • cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:* Versions 5.4.0 to before 13.0.0 Vulnerable ·python-pillow

Remediation

Upgrade Pillow to version 13.0.0 or later. Red Hat AI Inference Server 3.5 is fixed by RHSA-2026:94738, RHSA-2026:94721, RHSA-2026:94717, RHSA-2026:94715, RHSA-2026:94709 and RHSA-2026:94702. Red Hat plans no fix for Exploit Intelligence and lists Lightspeed Core, OpenShift Lightspeed, Red Hat Enterprise Linux 8 and other products as affected without a fix.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

  • Fix · CNA Pillow (python-pillow) Fixed in 13.0.0
  • Fix · GHSA-74r2-7ff9-mjj2 Pillow (PyPI) Fixed in 13.0.0 Advisory →

Red Hat 6 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
Show 3 more Red Hat advisories
  • 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

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Exploit IntelligenceAffectedNo fix planned: Out of support scope
Lightspeed CoreAffectedNo fix yet: Fix deferred
OpenShift LightspeedAffectedNo fix yet: Fix deferred
Red Hat AI Inference ServerAffectedNo fix yet: Fix deferred
Red Hat Ansible Automation Platform 2AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet: Fix deferred
Red Hat Lightspeed Services for OCPAffectedNo fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred
Red Hat Quay 3AffectedNo fix yet: Fix deferred
Red Hat Satellite 6AffectedNo fix yet: Fix deferred
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

Timeline

  1. 2026-10-20 Threatist record created from CVE-2026-112401
  2. 2026-10-20 Affected versions changed · Red Hat
  3. 2026-10-20 CVSS score added · Red Hat
  4. 2026-10-20 CISA SSVC decision points changed
  5. 2026-10-20 Priority changed: MEDIUM → LOW
  6. 2026-10-21 Alias added: GHSA-74r2-7ff9-mjj2
  7. 2026-10-21 Fix available: PyPI/[email protected] · GHSA-74r2-7ff9-mjj2
  8. 2026-10-21 CVSS score added · GHSA-74r2-7ff9-mjj2
  9. 2026-10-21 Weakness changed · GHSA-74r2-7ff9-mjj2
  10. 2026-10-21 5 new references · GHSA-74r2-7ff9-mjj2
  11. 2026-10-27 CVSS score added · NVD
  12. 2026-10-28 EPSS moved to the 50th–90th percentile
  13. 2026-11-04 Fix available: RHSA-2026:94717 · Red Hat
  14. 2026-11-04 Fix available: RHSA-2026:94715 · Red Hat
  15. 2026-11-04 Fix available: RHSA-2026:94709 · Red Hat
  16. 2026-11-04 Fix available: RHSA-2026:94738 · Red Hat
  17. 2026-11-04 Fix available: RHSA-2026:94702 · Red Hat
  18. 2026-11-04 Fix available: RHSA-2026:94721 · Red Hat
  19. 2026-11-04 Fix available: Red Hat AI Inference Server 3.5 · Red Hat

References

  • 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