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Fencer Intel
high 7.5

CVE-2026-54275 json

AIOHTTP: TLS Server Hostname Override Is Ignored When Reusing HTTPS Connections

published 5mo ago modified 17d ago also EUVD-2026-38312 , GHSA-4m7w-qmgq-4wj5 , PYSEC-2026-237

cvss
7.5
version 3.1, NVD
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

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, the server_hostname TLS SNI check can be bypassed when an existing connection is reused. If an application makes multiple requests to the same domain, but with different per-request server_hostname parameters, then the later calls may succeed by reusing the existing connection when they should have been rejected due to the TLS SNI check. This vulnerability is fixed in 3.14.1.

Patch / fix

  • pypi aiohttp 3.14.1
  • aiohttp aiohttp 3.14.1
  • python-aiohttp Debian 14 3.14.1-1

debian advisories DEBIAN-CVE-2026-54275

  • python-aiohttp SLE Module for Public Cloud 15 SP7, SLE Module for Public Cloud 15 SP6, SLE Module for Public Cloud 15 SP5 +1 more 3.6.0-150100.3.38.1
  • python-aiohttp SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +9 more 3.9.3-150400.10.43.1
  • python-aiohttp SLES for SAP applications 16.0, SLES 16.0 3.11.16-160000.6.1

suse advisories SUSE-SU-2026:3208-1SUSE-SU-2026:3207-1SUSE-SU-2026:22819-1

  • python-aiohttp openSUSE Leap 16.0 3.11.16-160000.6.1
  • python-aiohttp openSUSE Tumbleweed 3.14.1-1.1

opensuse advisories openSUSE-SU-2026:21372-1openSUSE-SU-2026:11097-1

Is CVE-2026-54275 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-2026-54275 updated cvss 4.8

aiohttp: AIOHTTP: TLS SNI check bypass via connection reuse

  • Red Hat Exploit Intelligence exploit-intelligence-tech-preview/vulnerability-analysis-rhel9
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Migration Toolkit for Applications 8 mta/mta-solution-server-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-cpu-rhel9, rhaii/vllm-tpu-rhel9, rhaii/vllm-cuda-rhel9, rhaii/vllm-rocm-rhel9, rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9, +9 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ansible Automation Platform 2 python-aiohttp, automation-controller, ansible-automation-platform-26/hub-rhel9, ansible-automation-platform-27/hub-rhel9, ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-25/lightspeed-rhel8, +19 more
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat Ansible Automation Platform Ansible Core 2 ansible-automation-platform-tech-preview/ee-minimal-rhel8, ansible-automation-platform-tech-preview/ee-minimal-rhel9 Red Hat Discovery 2 discovery/discovery-server-rhel9 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/bootc-azure-cuda-rhel9, +1 more Red Hat OpenShift AI (RHOAI) rhoai/odh-automl-rhel9, rhoai/odh-mlflow-rhel9, rhoai/odh-autorag-rhel9, rhoai/odh-mlserver-rhel9, rhoai/odh-caikit-nlp-rhel9, rhoai/odh-vllm-gaudi-rhel9, +45 more Red Hat Satellite 6 python-aiohttp, python3-aiohttp, satellite/iop-insights-engine-rhel9, satellite/iop-vulnerability-engine-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ansible Automation Platform Ansible Core 2 ansible-automation-platform/ee-minimal-rhel8, ansible-automation-platform/ee-minimal-rhel9 Red Hat Hardened Images mariadb11.8 Red Hat Satellite 6 python-aiohttp, python3-aiohttp Red Hat Update Infrastructure 4 for Cloud Providers python-aiohttp
    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
no
Technical impact
partial
Assessed
4mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 2.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U
CNA 4.0 2.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/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 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 aiohttp
<3.14.1
3.14.1

Affected products

  • aio-libs aiohttp

Classification

Weakness
  • CWE-297 Improper Validation of Certificate with Host Mismatch

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 aio-libs/aiohttp published their own advisory on GitHub. Reviewed sources take precedence over it.

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