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Fencer Intel
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 5mo ago modified last mo. also EUVD-2026-32016 , GHSA-86qp-5c8j-p5mr , PYSEC-2026-161

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

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

Is CVE-2026-48710 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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
2mo ago
Patch by
2026-09-16 (last mo.)
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
2mo ago

Exploit prediction

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

Exploits and checks

  • 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
GitHub 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

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 Intel 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.

The maintainers of Kludex/starlette published their own advisory on GitHub. Reviewed sources take precedence over it.