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Fencer Vulns
medium 6.5

CVE-2026-96637 json

Pillow: Decompression bomb check bypass in SpiderImagePlugin.seek() leads to unbounded allocation DoS

published 2026-10-21 18 d ago modified 2026-10-29 11 d ago also BIT-pillow-2026-96637 , EUVD-2026-107569 , GHSA-g842-9rc4-69pw , PYSEC-2026-4338

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

Pillow is a Python imaging library. Prior to 13.0.0, SpiderImageFile.seek() in src/PIL/SpiderImagePlugin.py reparses a later SPIDER stack frame and replaces self._size without rerunning Image._decompression_bomb_check(). A tiny file can use a safe first frame to pass Image.open() and then declare very large dimensions in a later mode F frame. Loading that frame allocates approximately four bytes per attacker-declared pixel and can consume multiple gigabytes of memory. This issue is fixed in version 13.0.0.

Patch / fix

  • pypi pillow 13.0.0
  • bitnami pillow 13.0.0
  • python pillow 13.0.0
  • python-Pillow SLE Module for Package Hub 15 SP7 7.2.0-150300.3.33.1

suse advisories SUSE-SU-2026:5038-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-96637 updated cvss 6.5

pillow: pillow: Denial of Service via decompression bomb bypass in SPIDER images

  • Red Hat Exploit Intelligence exploit-intelligence/vulnerability-analysis-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Lightspeed Core lightspeed-core/rag-tool-cpu-rhel9, lightspeed-core/lightspeed-stack-rhel9, lightspeed-core/rag-tool-cuda-12.9-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9, openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 Red Hat AI Inference Server rhaii/vllm-tpu-rhel9, rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9, rhaiis/vllm-cuda-rhel9, rhaiis/vllm-rocm-rhel9, rhaii/vllm-neuron-rhel9, +3 more
    affected: no fix available “Fix deferred”
  • Red Hat Ansible Automation Platform 2 python-pillow 10.3.0-1.el9ap, python3x-pillow 10.3.0-1.el8ap, python3.11-pillow 10.3.0-1.el8ap, python3.12-pillow 12.3.0-1.el9ap, ansible-automation-platform-26/hub-rhel9, ansible-automation-platform-27/hub-rhel9, +4 more
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 python3-pillow, python3-pillow-tk, python-pillow 10.3.0-1.el9ap Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-gcp-cuda-rhel9, rhelai3/disk-image-cuda-rhel9, +2 more Red Hat Lightspeed Services for OCP lightspeed-services-ocp/ocp-rules-rhel9 Red Hat OpenShift AI (RHOAI) rhai/guidellm-rhel9, rhoai/odh-automl-rhel9, rhoai/odh-mlflow-rhel9, rhoai/odh-autorag-rhel9, rhoai/odh-ogx-core-rhel9, rhoai/odh-vllm-gaudi-rhel9, +38 more
    affected: no fix available “Fix deferred”
  • Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Satellite 6 python-pillow 10.3.0-1.el9ap, python3.12-pillow 12.3.0-1.el9ap
    affected: no fix available “Fix deferred”
  • Red Hat AI Inference Server 3.5 rhaii/vllm-cpu-rhel9 1793444554, rhaii/vllm-cuda-rhel9 1793444600, rhaii/vllm-rocm-rhel9 1793444456, rhaii/vllm-gaudi-rhel9 1793444510, rhaii/vllm-spyre-rhel9 1793444409, rhaii/model-opt-cuda-rhel9 1793444339
    fixed: vendor fix RHSA-2026:94715

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
17 d ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 7.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 7.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi pillow
<13.0.0
13.0.0
bitnami pillow
<13.0.0
13.0.0

Affected products

  • python-pillow Pillow

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.