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Fencer Vulns
high 7.5

CVE-2026-54283 json

Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS

published 2026-06-15 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-38319 , GHSA-82w8-qh3p-5jfq , PYSEC-2026-249

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

Starlette is a lightweight ASGI framework/toolkit. From 0.4.1 until 1.3.1, request.form() accepts max_fields and max_part_size to bound resource consumption while parsing form data. These limits are enforced for multipart/form-data, but silently ignored for application/x-www-form-urlencoded. An unauthenticated attacker can therefore send a urlencoded body with an arbitrarily large number of fields or an arbitrarily large field, even when the application configured limits it believed would apply. This vulnerability is fixed in 1.3.1.

Patch / fix

  • pypi starlette 1.3.1
  • encode starlette 1.3.1
  • kludex starlette 1.3.1
  • starlette Debian 12 0.26.1-1+deb12u2
  • starlette Debian 13 0.46.1-3+deb13u3
  • starlette Debian 14 1.3.1-1

debian advisories DEBIAN-CVE-2026-54283

  • python-starlette SLES for SAP applications 16.0, SLES 16.0 0.41.3-160000.4.1

suse advisories SUSE-SU-2026:22360-1

  • python-starlette openSUSE Leap 16.0 0.41.3-160000.4.1

opensuse advisories openSUSE-SU-2026:21053-1

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-2026-54283 updated cvss 7.5

starlette: Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS

  • Red Hat Exploit Intelligence exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed/lightspeed-agentic-sandbox-rhel9
    affected: workaround, no fix available
  • Red Hat AI Inference Server rhaii/vllm-tpu-rhel9, rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9, rhaii/vllm-gaudi-rhel9, rhaii/vllm-neuron-rhel9, rhaiis/vllm-spyre-rhel9, +1 more Red Hat Ansible Automation Platform 2 ansible-automation-platform-25/lightspeed-chatbot-rhel8 Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-gaudi-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-caikit-tgis-serving-rhel9, rhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9 Red Hat OpenShift Virtualization 4 container-native-virtualization/ocp-virt-validation-checkup-rhel9
    affected: workaround, no fix available
  • Red Hat AI Inference Server 3.2 rhaiis/vllm-cuda-rhel9 1782951012, rhaiis/vllm-cuda-rhel9 1787860580, rhaiis/vllm-rocm-rhel9 1782951244
    fixed: vendor fix RHSA-2026:61627
  • Red Hat AI Inference Server 3.4 rhaii/vllm-cpu-rhel9 1789681128, rhaii/vllm-cpu-rhel9 1790075793, rhaii/vllm-cuda-rhel9 1789681126, rhaii/vllm-cuda-rhel9 1790090131, rhaii/vllm-rocm-rhel9 1789681126, rhaii/vllm-rocm-rhel9 1790109620, +2 more
    fixed: vendor fix RHSA-2026:69466
  • Red Hat Ansible Automation Platform 2.6 ansible-automation-platform-26/mcp-tools-rhel9 1783920640, ansible-automation-platform-26/lightspeed-chatbot-rhel9 1785646188
    fixed: vendor fix RHSA-2026:50479
  • Red Hat Ansible Automation Platform 2.7 ansible-automation-platform-27/mcp-tools-rhel9 1783918403, ansible-automation-platform-27/lightspeed-chatbot-rhel9 1785426734
    fixed: vendor fix RHSA-2026:50340
  • Red Hat Enterprise Linux AI 3.4 rhelai3/bootc-cuda-rhel9 1790868254, rhelai3/bootc-rocm-rhel9 1790614447, rhelai3/bootc-aws-cuda-rhel9 1790881122, rhelai3/bootc-gcp-cuda-rhel9 1790881123, rhelai3/disk-image-cuda-rhel9 1790957417, rhelai3/bootc-azure-cuda-rhel9 1790881120, +1 more
    fixed: vendor fix RHSA-2026:76150
show 7 more
  • Red Hat Migration Toolkit for Applications 8.2 mta/mta-solution-server-rhel9 1784109883
    fixed: vendor fix RHSA-2026:43038
  • Red Hat OpenShift AI 2.25 rhoai/odh-caikit-nlp-rhel9 1791448212, rhoai/odh-feature-server-rhel9 1792148523, rhoai/odh-built-in-detector-rhel9 1791364320, rhoai/odh-guardrails-detector-huggingface-runtime-rhel9 1791367475
    fixed: vendor fix RHSA-2026:87410
  • Red Hat OpenShift AI 3.3 rhoai/odh-mlflow-rhel9 1789653606, rhoai/odh-mlserver-rhel9 1789121365, rhoai/odh-vllm-gaudi-rhel9 1789121263, rhoai/odh-llama-stack-core-rhel9 1789121286
    fixed: vendor fix RHSA-2026:73987
  • Red Hat OpenShift AI 3.4 rhoai/odh-automl-rhel9 1791535789, rhoai/odh-mlflow-rhel9 1787226790, rhoai/odh-mlserver-rhel9 1791446063, rhoai/odh-feature-server-rhel9 1791863220, rhoai/odh-llama-stack-core-rhel9 1790958470, rhoai/odh-built-in-detector-rhel9 1791537794, +21 more
    fixed: vendor fix RHSA-2026:84734
  • Red Hat Satellite 6.17 satellite/iop-advisor-engine-rhel9 1784834402
    fixed: vendor fix RHSA-2026:44696
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9
    not affected: component not present
  • Red Hat Ansible Automation Platform 2.6 ansible-automation-platform-26/hub-rhel9 1783979593, ansible-automation-platform-26/hub-rhel9 1785753568, ansible-automation-platform-26/gateway-rhel9 1783969842, ansible-automation-platform-26/gateway-rhel9 1785780020, ansible-automation-platform-26/hub-web-rhel9 1783982443, ansible-automation-platform-26/hub-web-rhel9 1785756951, +54 more Red Hat Ansible Automation Platform 2.7 ansible-automation-platform-27/hub-rhel9 1783919521, ansible-automation-platform-27/hub-rhel9 1785376164, ansible-automation-platform-27/gateway-rhel9 1783919486, ansible-automation-platform-27/gateway-rhel9 1785435970, ansible-automation-platform-27/hub-web-rhel9 1783921568, ansible-automation-platform-27/hub-web-rhel9 1785379466, +56 more Red Hat Enterprise Linux command line assistant rhel-cla/rhel-knowledge-bridge-rhel10 Red Hat Hardened Images jaeger 2.19.0-1.hum1 Red Hat Migration Toolkit for Applications 8.2 mta/mta-ui-rhel9 1783962515, mta/mta-cli-rhel9 1784211378, mta/mta-hub-rhel9 1784059743, mta/mta-rhel9-operator 1784219586, mta/mta-operator-bundle 1784220119, mta/mta-analyzer-addon-rhel9 1784163267, +7 more Red Hat OpenShift AI (RHOAI) rhoai/odh-kserve-agent-rhel9, rhoai/odh-kserve-router-rhel9, rhoai/odh-llm-d-kv-cache-rhel9, rhoai/odh-kserve-controller-rhel9, rhoai/odh-kserve-storage-initializer-rhel9
    +4 more products
    Red Hat OpenShift AI 2.25 rhoai/odh-rhel9-operator 1792570619, rhoai/odh-vllm-cpu-rhel9 1792018436, rhoai/odh-dashboard-rhel9 1791853525, rhoai/odh-modelmesh-rhel9 1790881700, rhoai/odh-operator-bundle 1792571069, rhoai/odh-vllm-cuda-rhel9 1791358976, +62 more Red Hat OpenShift AI 3.3 rhoai/odh-cli-rhel9 1790070206, rhoai/rhai-cli-rhel9 1790070206, rhoai/odh-trainer-rhel9 1790136369, rhoai/odh-maas-api-rhel9 1790131842, rhoai/odh-rhel9-operator 1790686009, rhoai/odh-vllm-cpu-rhel9 1790274961, +73 more Red Hat OpenShift AI 3.4 rhoai/odh-cli-rhel9 1787330837, rhoai/odh-cli-rhel9 1791509689, rhoai/rhai-cli-rhel9 1787330837, rhoai/rhai-cli-rhel9 1791509689, rhoai/odh-automl-rhel9 1786612415, rhoai/odh-mlflow-rhel9 1791865967, +179 more Red Hat Satellite 6 satellite/iop-vmaas-rhel9, satellite/foreman-mcp-server-rhel9, satellite/iop-host-inventory-rhel9, satellite/iop-vulnerability-engine-rhel9
    not affected: vulnerable code not present

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
4 mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi starlette
>=0.4.1, <1.3.1
1.3.1

Affected products

  • Kludex starlette

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

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.