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Fencer Vulns
high 7.5

CVE-2026-54277 json

AIOHTTP: C HTTP Parser Bypasses max_line_size for Fragmented Lines

published 2026-06-15 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-38314 , GHSA-63hw-fmq6-xxg2 , PYSEC-2026-2110

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, it is possible to bypass the max_line_size check in parts of an HTTP request in the C parser. If using the optimised C parser (the default in pre-built wheels), then an attacker may be able to send oversized lines through the HTTP parser and use an excessive amount of memory, potentially leading to DoS. This vulnerability is fixed in 3.14.1.

Patch / fix

  • pypi aiohttp 3.14.1
  • aiohttp aiohttp 3.14.1
  • python-aiohttp Debian 12 3.8.4-1+deb12u2
  • python-aiohttp Debian 14 3.14.1-1

debian advisories DEBIAN-CVE-2026-54277

  • 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

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-2026-54277 updated cvss 5.9

aiohttp: aiohttp: Denial of Service via oversized HTTP request lines bypassing max_line_size check

  • Red Hat AI Inference Server rhaiis/vllm-spyre-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-vllm-gaudi-rhel9, rhoai/odh-ta-lmes-job-rhel9, +41 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 Exploit Intelligence exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 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, +8 more 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 Red Hat Ansible Automation Platform Ansible Core 2 ansible-automation-platform/ee-minimal-rhel8, ansible-automation-platform/ee-minimal-rhel9, ansible-automation-platform-tech-preview/ee-minimal-rhel8, ansible-automation-platform-tech-preview/ee-minimal-rhel9
    not affected: vulnerable code not present
  • Red Hat Hardened Images mariadb11.8
    not affected: vulnerable code not in execute path
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-caikit-nlp-rhel9, rhoai/odh-caikit-tgis-serving-rhel9, rhoai/odh-openvino-model-server-rhel9, rhoai/odh-ml-pipelines-runtime-generic-rhel9 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
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.56% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
CNA 4.0 6.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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-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.