Pillow decompression-bomb check bypassed by multi-frame seek()
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 1 fixed, 11 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.
Summary
Pillow before 13.0.0 is affected. MpoImageFile.seek() and DcxImageFile.seek() reparse later frames without rerunning the decompression-bomb check (CWE-400), so a crafted multi-frame image can pass Image.open() with a tiny first frame and then declare an over-limit later frame. A remote attacker who gets a user to process such an image can exhaust memory and cause a denial of service.
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, MpoImageFile.seek() and DcxImageFile.seek() reparse later MPO or DCX frames and replace self._size without rerunning Image._decompression_bomb_check(). A crafted multi-frame image can use a tiny first frame to pass Image.open() and then declare an over-limit later frame. Normal frame iteration through seek(), load(), or ImageSequence.Iterator can decode that frame and commit hundreds of megabytes or more, causing memory-exhaustion 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
- Poc
- Automatable
- No
- 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 | before 13.0.0 | 13.0.0 | Patch available | CNA |
| — | Pillow (PyPI) | before 13.0.0 | 13.0.0 | Patch available | GHSA-p8hx-v2p6-rp84 |
- 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-p8hx-v2p6-rp84
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:* | before 13.0.0 | Vulnerable | python-pillow |
- cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:* Versions before 13.0.0 Vulnerable ·python-pillow
Remediation
Upgrade Pillow to 13.0.0. 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 has no fix planned for Exploit Intelligence and no fix available for Lightspeed Core, OpenShift Lightspeed, Red Hat Ansible Automation Platform 2, Red Hat Enterprise Linux 8 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-p8hx-v2p6-rp84 Pillow (PyPI) Fixed in 13.0.0 Advisory →
Red Hat 6 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
Show 3 more Red Hat advisories
- 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
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Exploit Intelligence | Affected | No fix planned: Out of support scope |
| Lightspeed Core | Affected | No fix yet: Fix deferred |
| OpenShift Lightspeed | Affected | No fix yet: Fix deferred |
| Red Hat AI Inference Server | Affected | No fix yet: Fix deferred |
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet: Fix deferred |
| Red Hat Lightspeed Services for OCP | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat Quay 3 | Affected | No fix yet: Fix deferred |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
| 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 |
Timeline
- 2026-10-21 Threatist record created from CVE-2026-96636
- 2026-10-22 Alias added: GHSA-p8hx-v2p6-rp84
- 2026-10-22 Fix available: PyPI/[email protected] · GHSA-p8hx-v2p6-rp84
- 2026-10-22 CVSS score added · GHSA-p8hx-v2p6-rp84
- 2026-10-22 Weakness changed · GHSA-p8hx-v2p6-rp84
- 2026-10-22 6 new references · GHSA-p8hx-v2p6-rp84
- 2026-10-23 Affected versions changed · Red Hat
- 2026-10-23 CVSS score added · Red Hat
- 2026-10-23 Priority changed: MEDIUM → LOW
- 2026-10-30 CISA SSVC decision points changed
- 2026-10-30 Priority changed: LOW → MEDIUM
- 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-2026:94721 · Red Hat
- 2026-11-04 Fix available: Red Hat AI Inference Server 3.5 · Red Hat
References
Advisory 2
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-2026-96636 · CVE Program
- CVE-2026-96636 · NVD
- FIRST EPSS
- GHSA-p8hx-v2p6-rp84 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-96636 · Red Hat security data · CC BY 4.0
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