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Regular expression denial of service in Pillow XBM image parser

Priority LOW 37CWE-1333Published · 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-1333.

Summary

Pillow before 13.0.0 contains a regular expression denial of service in its XBM header parser (CWE-1333). A remote, unauthenticated attacker can supply a small crafted XBM file that stalls a worker for minutes when an application calls Image.open() on it. A public exploit is linked in the references.

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

Description from the CNA

Pillow is a Python imaging library. Prior to 13.0.0, Pillow's XBM header parser is vulnerable to regular-expression denial of service. In XbmImageFile._open, when an application calls Image.open() on a small crafted XBM file, XbmImagePlugin applies a backtracking expression to the attacker-controlled header before image dimensions are accepted, stalling a worker for minutes and denying service. This issue is fixed in version 13.0.0.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00532 45th 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-pillowPillowbefore 13.0.013.0.0Patch availableCNA
—Pillow (PyPI)before 13.0.013.0.0Patch availableGHSA-xgh8-jp6q-p5x8
  • Pillow Vendorpython-pillow Affected before 13.0.0 Fixed in 13.0.0 Patch available CNA
  • Pillow (PyPI) Vendor— Affected before 13.0.0 Fixed in 13.0.0 Patch available GHSA-xgh8-jp6q-p5x8

CPE configurations NVD · 1

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

Remediation

Upgrade Pillow to 13.0.0 or later. Red Hat fixes Red Hat AI Inference Server 3.5 in RHSA-2026:94702, RHSA-2026:94709, RHSA-2026:94715, RHSA-2026:94717, RHSA-2026:94721 and RHSA-2026:94738. The sources list no fixed version for Exploit Intelligence, Lightspeed Core, OpenShift Lightspeed, Red Hat AI Inference Server, Red Hat Ansible Automation Platform 2 and other products.

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-xgh8-jp6q-p5x8 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-2026-112901
  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-xgh8-jp6q-p5x8
  7. 2026-10-21 Fix available: PyPI/[email protected] · GHSA-xgh8-jp6q-p5x8
  8. 2026-10-21 CVSS score added · GHSA-xgh8-jp6q-p5x8
  9. 2026-10-21 Weakness changed · GHSA-xgh8-jp6q-p5x8
  10. 2026-10-21 5 new references · GHSA-xgh8-jp6q-p5x8
  11. 2026-10-27 CVSS score added · NVD
  12. 2026-11-04 Fix available: RHSA-2026:94717 · Red Hat
  13. 2026-11-04 Fix available: RHSA-2026:94715 · Red Hat
  14. 2026-11-04 Fix available: RHSA-2026:94709 · Red Hat
  15. 2026-11-04 Fix available: RHSA-2026:94738 · Red Hat
  16. 2026-11-04 Fix available: RHSA-2026:94702 · Red Hat
  17. 2026-11-04 Fix available: RHSA-2026:94721 · Red Hat
  18. 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