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Fencer Vulns
medium 6.5

CVE-2026-48710 kev in the critical feed json

Starlette has missing Host header validation that poisons request.url.path, bypassing path-based security checks

published 2026-05-22 5 mo ago modified 2026-10-01 38 d ago also GHSA-86qp-5c8j-p5mr , PYSEC-2026-161 , EUVD-2026-32016

cvss
6.5
version 3.1, CNA
cisa kev
Exploited
added 2026-09-02
epss
70.3%
EPSS 70.3% chance of exploitation in 30 days, percentile 99.3%
public exploits
0
none known, plus a Nuclei check

Summary

Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP `Host` request header was not validated before being used to reconstruct `request.url`. Because the routing algorithm relies on the raw HTTP path while `request.url` is rebuilt from the `Host` header, a malformed header could make `request.url.path` differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on `request.url` (rather than the raw `scope` path) could therefore be bypassed. Users should upgrade to a version greater than or equal to version 1.0.1, which validates the `Host` header against the grammar of RFC 9112 §3.2 / RFC 3986 §3.2.2 when constructing `request.url` and falls back to `scope["server"]` for malformed values.

Patch / fix

cisa required action Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

  • pypi starlette 1.0.1
  • Red Hat Red Hat AI Inference Server 3.3 1782352847, 1782353093
  • Red Hat Red Hat Ansible Automation Platform 2.6 1780102732
  • Red Hat Red Hat Ansible Automation Platform 2.7 1780099185
  • Red Hat Red Hat Migration Toolkit for Applications 8.2 1784109883
  • Red Hat Red Hat OpenShift AI 3.3 1782471661, 1782471672, 1782471730, 1782471731, 1782471732, 1782471734, 1782471740, 1782471753, 1782471796, 1782471834, 1782471849, 1782472374, 1782991170, 1782997656
  • Red Hat Red Hat OpenShift AI 3.4 1782132126, 1782132379, 1782132403, 1782132444, 1782132473, 1782132493, 1782132564, 1782132660, 1782132686, 1782132767, 1782133337, 1782133865, 1782133907, 1782135300, 1782301637, 1782420349, 1786612415, 1787068065
  • Red Hat Red Hat Satellite 6.17 1784834402
  • Red Hat Red Hat Satellite 6.18 1780414237, 1780492008, 1784554123
  • Red Hat Red Hat Satellite 6.19 1780403026, 1780492012, 1782139619, 1788190224
  • starlette Debian 12 0.26.1-1+deb12u1
  • starlette Debian 13 0.46.1-3+deb13u2
  • starlette Debian 14 1.1.0-1

debian advisories DEBIAN-CVE-2026-48710

  • python-starlette SLES for SAP applications 16.0, SLES 16.0 0.41.3-160000.3.1

suse advisories SUSE-SU-2026:22151-1

  • python-starlette openSUSE Leap 16.0 0.41.3-160000.3.1
  • python-google-adk openSUSE Tumbleweed 2.2.0-1.1
  • python-starlette openSUSE Tumbleweed 1.2.0-1.1

opensuse advisories openSUSE-SU-2026:20975-1openSUSE-SU-2026:11044-1openSUSE-SU-2026:11026-1

  • py3-starlette Alpine 3.24 1.1.0-r0

alpine advisories ALPINE-CVE-2026-48710

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2026-48710 updated cvss 6.5

starlette: Starlette: Security restriction bypass via malformed HTTP Host header

  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-service-api-rhel9
    affected: workaround, no fix available
  • Red Hat AI Inference Server rhaii/vllm-tpu-rhel9, rhaii/vllm-rocm-rhel9, rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9, rhaii/vllm-gaudi-rhel9, rhaii/vllm-neuron-rhel9, +2 more
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat Ansible Automation Platform 2 ansible-automation-platform-25/lightspeed-chatbot-rhel8
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/bootc-azure-rocm-rhel9
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-vllm-cuda-rhel9, rhoai/odh-vllm-rocm-rhel9, rhoai/odh-caikit-nlp-rhel9, rhoai/odh-vllm-gaudi-rhel9, rhoai/odh-llm-d-kv-cache-rhel9, +5 more
    affected: workaround, no fix available
  • Red Hat AI Inference Server 3.3 rhaiis/vllm-cuda-rhel9 1782352847, rhaiis/vllm-rocm-rhel9 1782353093
    fixed: vendor fix RHSA-2026:30089
  • 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-spyre-rhel9 1789681201, rhaii/vllm-spyre-rhel9 1790076141
    fixed: vendor fix RHSA-2026:69466
  • Red Hat Ansible Automation Platform 2.6 ansible-automation-platform-26/lightspeed-chatbot-rhel9 1780102732
    fixed: vendor fix RHSA-2026:24866
show 12 more
  • Red Hat Ansible Automation Platform 2.7 ansible-automation-platform-27/lightspeed-chatbot-rhel9 1780099185
    fixed: vendor fix RHSA-2026:23346
  • Red Hat Enterprise Linux AI 3.4 rhelai3/bootc-cuda-rhel9 1790868254, rhelai3/bootc-aws-cuda-rhel9 1790881122, rhelai3/bootc-gcp-cuda-rhel9 1790881123, rhelai3/disk-image-cuda-rhel9 1790957417, rhelai3/bootc-azure-cuda-rhel9 1790881120
    fixed: vendor fix RHSA-2026:76150
  • 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-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-feature-server-rhel9 1782997656, rhoai/odh-training-cuda128-torch29-py312-rhel9 1782991170, rhoai/odh-trustyai-garak-lls-provider-dsp-rhel9 1782472374, rhoai/odh-trustyai-garak-lls-provider-dsp-rhel9 1790085310, rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9 1782471731, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9 1782471849, +9 more
    fixed: vendor fix RHSA-2026:37275
  • Red Hat OpenShift AI 3.4 rhoai/odh-automl-rhel9 1786612415, rhoai/odh-feature-server-rhel9 1787068065, rhoai/odh-llama-stack-core-rhel9 1782132126, rhoai/odh-kserve-autogluon-server-rhel9 1791300023, rhoai/odh-trustyai-garak-lls-provider-dsp-rhel9 1782133907, rhoai/odh-trustyai-nemo-guardrails-server-rhel9 1782420349, +13 more
    fixed: vendor fix RHSA-2026:60520
  • Red Hat Satellite 6.17 satellite/iop-advisor-engine-rhel9 1784834402
    fixed: vendor fix RHSA-2026:44696
  • Red Hat Satellite 6.18 satellite/foreman-mcp-server-rhel9 1780492008, satellite/iop-host-inventory-rhel9 1780414237, satellite/iop-vulnerability-engine-rhel9 1784554123
    fixed: vendor fix RHSA-2026:22993
  • Red Hat Satellite 6.19 satellite/iop-vmaas-rhel9 1782139619, satellite/foreman-mcp-server-rhel9 1780492012, satellite/iop-host-inventory-rhel9 1780403026, satellite/iop-vulnerability-engine-rhel9 1788190224
    fixed: vendor fix RHSA-2026:22992
  • Red Hat Exploit Intelligence exploit-intelligence-tech-preview/vulnerability-analysis-rhel9
    not affected: vulnerable code not present
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat Ansible Automation Platform 2 ansible-automation-platform-26/mcp-tools-rhel9 Red Hat Ansible Automation Platform 2.6 ansible-automation-platform-26/hub-rhel9 1779761061, ansible-automation-platform-26/gateway-rhel9 1779773804, ansible-automation-platform-26/hub-web-rhel9 1779765164, ansible-automation-platform-26/receptor-rhel9 1779770938, ansible-automation-platform-26/mcp-tools-rhel9 1779772877, ansible-automation-platform-26/controller-rhel9 1779762270, +23 more Red Hat Ansible Automation Platform 2.7 ansible-automation-platform-27/hub-rhel9 1780534559, ansible-automation-platform/platform-operator-bundle 1780540049, ansible-automation-platform/platform-operator-bundle 1780540445 Red Hat Enterprise Linux AI 3.4 rhelai3/bootc-rocm-rhel9 1790614447, rhelai3/bootc-azure-rocm-rhel9 1790707552 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-mlserver-rhel9, rhoai/odh-kserve-agent-rhel9, rhoai/odh-kserve-router-rhel9, rhoai/odh-kserve-controller-rhel9
    +3 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, +64 more Red Hat OpenShift AI 3.3 rhoai/odh-cli-rhel9 1782471642, rhoai/odh-cli-rhel9 1790070206, rhoai/rhai-cli-rhel9 1782471642, rhoai/rhai-cli-rhel9 1790070206, rhoai/odh-mlflow-rhel9 1782917849, rhoai/odh-mlflow-rhel9 1789653606, +145 more Red Hat OpenShift AI 3.4 rhoai/odh-cli-rhel9 1782132151, rhoai/odh-cli-rhel9 1787330837, rhoai/odh-cli-rhel9 1791509689, rhoai/rhai-cli-rhel9 1782132151, rhoai/rhai-cli-rhel9 1787330837, rhoai/rhai-cli-rhel9 1791509689, +293 more
    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

Timeline

  1. Published
  2. Added to CISA KEV
  3. CISA SSVC: exploitation active
  4. CISA patch deadline

Known exploited

Added
2 mo ago
Patch by
2026-09-16 (54 d ago)
Ransomware
Not known
Required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Vendor, product
Kludex, Starlette
CISA name
Kludex Starlette HTTP Request/Response Smuggling Vulnerability

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

70.29% chance of exploitation in the next 30 days, higher than 99.3% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Starlette - Improper Validation of Unsafe Equivalence in Input nuclei detection template
  • secwest.net https://www.secwest.net/starlette referenced PoC, tagged "exploit" by a source, unverified
  • x41-dsec.de https://www.x41-dsec.de/lab/advisories/x41-2026-002-starlette referenced PoC, tagged "exploit" by a source, unverified
  • wiz.io https://www.wiz.io/blog/ai-infrastructure-honeypot referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi starlette
<1.0.1
1.0.1

Affected products

  • Kludex starlette
  • Red Hat Red Hat AI Inference Server 3.3
  • Red Hat Red Hat Ansible Automation Platform 2.6
  • Red Hat Red Hat Ansible Automation Platform 2.7
  • Red Hat Red Hat Migration Toolkit for Applications 8.2
  • Red Hat Red Hat OpenShift AI 3.3
  • Red Hat Red Hat OpenShift AI 3.4
  • Red Hat Red Hat Satellite 6.17
  • Red Hat Red Hat Satellite 6.18
  • Red Hat Red Hat Satellite 6.19
  • Red Hat Exploit Intelligence
  • Red Hat OpenShift Lightspeed
  • Red Hat Red Hat AI Inference Server
  • Red Hat Red Hat Ansible Automation Platform 2
  • Red Hat Red Hat Enterprise Linux AI (RHEL AI) 3
  • Red Hat Red Hat OpenShift AI (RHOAI)

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests
  • CWE-1289 Improper Validation of Unsafe Equivalence in Input

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.