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TI-2026-22636 Aliases CVE-2026-28356GHSA-p2m9-wcp5-6qw3

ReDoS in multipart 1.3.0 - `parse_options_header()`

Priority MEDIUM 40CWE-1333Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 3 fixed, 5 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-1333.

Summary

multipart is a fast multipart/form-data parser for python. Prior to 1.2.2, 1.3.1 and 1.4.0-dev, the parse_options_header() function in multipart.py uses a regular expression with an ambiguous alternation, which can cause exponential backtracking (ReDoS) when parsing maliciously crafted HTTP or multipart segment headers. This can be abused for denial of service (DoS) attacks against web applications using this library to parse request headers or multipart/form-data streams. The issue is fixed in 1.2.2, 1.3.1 and 1.4.0-dev.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00841 58th percentileScored 2026-11-07
Fix Partial multipart (defnull): 1.3.1, 1.2.2multipart (PyPI): 1.3.1, 1.2.2Red Hat: 7 advisoriesRed Hat: 3 fixed, 5 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
defnullmultipart1.3.0 to before 1.3.1; before 1.2.21.3.1, 1.2.2Patch availableCNA
—multipart (PyPI)1.3.0 to before 1.3.11.3.1Patch availableGHSA-p2m9-wcp5-6qw3
—multipart (PyPI)before 1.2.21.2.2Patch availableGHSA-p2m9-wcp5-6qw3
  • multipart Vendordefnull Affected 1.3.0 to before 1.3.1; before 1.2.2 Fixed in 1.3.1, 1.2.2 Patch available CNA
  • multipart (PyPI) Vendor— Affected 1.3.0 to before 1.3.1 Fixed in 1.3.1 Patch available GHSA-p2m9-wcp5-6qw3
  • multipart (PyPI) Vendor— Affected before 1.2.2 Fixed in 1.2.2 Patch available GHSA-p2m9-wcp5-6qw3

Remediation

  • Fix · CNA multipart (defnull) Fixed in 1.3.1, 1.2.2
  • Fix · GHSA-p2m9-wcp5-6qw3 multipart (PyPI) Fixed in 1.3.1 Advisory →
  • Fix · GHSA-p2m9-wcp5-6qw3 multipart (PyPI) Fixed in 1.2.2 Advisory →

Red Hat 7 advisories

  • RHSA-2026:73987 Released 2026-09-30 · Red Hat rating Critical
    RHOAI 3.3.7 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.3 registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9, registry.redhat.io/rhoai/odh-data-science-pipelines-argo-argoexec-rhel9 +47
  • RHSA-2026:42644 Released 2026-07-21 · Red Hat rating Important
    RHOAI 2.25.9 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 2.25 registry.redhat.io/rhoai/odh-caikit-tgis-serving-rhel9, registry.redhat.io/rhoai/odh-feature-server-rhel9, registry.redhat.io/rhoai/odh-kserve-storage-initializer-rhel9 +36
  • RHSA-2026:37275 Released 2026-07-09 · Red Hat rating Critical
    RHOAI 3.3.5 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.3 registry.redhat.io/rhoai/odh-dashboard-rhel9, registry.redhat.io/rhoai/odh-data-science-pipelines-operator-controller-rhel9, registry.redhat.io/rhoai/odh-feast-operator-rhel9 +45
Show 4 more Red Hat advisories
  • RHSA-2026:10184 Released 2026-04-23 · Red Hat rating Important
    RHOAI 2.25.5 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 2.25 registry.redhat.io/rhoai/odh-caikit-nlp-rhel9, registry.redhat.io/rhoai/odh-caikit-tgis-serving-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9 +47
  • RHSA-2026:6762 Released 2026-04-07 · Red Hat rating Important
    Red Hat AI Inference Server 3.2.2 (ROCm)
    • Red Hat AI Inference Server 3.2 registry.redhat.io/rhaiis/vllm-rocm-rhel9
  • RHSA-2026:6761 Released 2026-04-07 · Red Hat rating Important
    Red Hat AI Inference Server Model Optimization Tools 3.2.2 (CUDA)
    • Red Hat AI Inference Server 3.2 registry.redhat.io/rhaiis/model-opt-cuda-rhel9
  • RHSA-2026:5809 Released 2026-03-25 · Red Hat rating Important
    Red Hat AI Inference Server 3.2.2 (cuda-ubi9)
    • Red Hat AI Inference Server 3.2 registry.redhat.io/rhaiis/vllm-cuda-rhel9

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Lightspeed CoreAffectedNo fix yet
OpenShift LightspeedAffectedNo fix planned: Will not fix
Red Hat AI Inference ServerAffectedNo fix yet
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet
Red Hat Satellite 6AffectedNo fix yet
Red Hat AI Inference Server 3.2Fixed RHSA-2026:5809, RHSA-2026:6761, RHSA-2026:6762
Red Hat OpenShift AI 2.25Fixed RHSA-2026:10184, RHSA-2026:42644
Red Hat OpenShift AI 3.3Fixed RHSA-2026:37275, RHSA-2026:73987
Not affected: 6 products
  • OpenShift Lightspeed
  • Red Hat Ansible Automation Platform 2
  • Red Hat OpenShift AI (RHOAI)
  • Red Hat OpenShift AI 2.25
  • Red Hat OpenShift AI 3.3
  • Red Hat Satellite 6

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-28356
  2. 2026-10-03 Alias added: GHSA-p2m9-wcp5-6qw3
  3. 2026-10-07 Fix available: RHSA-2026:73987 · Red Hat
  4. 2026-11-06 Fix available: RHSA-2026:42644 · Red Hat

References

Advisory 1

Other 2

Sources

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