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Fencer Intel
high 7.5

CVE-2026-97689 json

urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory

published last mo. modified 29d ago also EUVD-2026-89017 , GHSA-vxq7-64xx-v4gw , PYSEC-2026-4177

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits
0
none known

Summary

urllib3 is an HTTP client library for Python. From 1.10.3 until 2.8.0, the HTTPResponse.read_chunked and HTTPResponse.stream methods can allocate unbounded memory because the streaming chunk parser buffers the chunk-size field until newline or EOF without a length bound. The trigger is that a malicious server returns Transfer-Encoding: chunked followed by a very long run of bytes without a newline. The attack mechanism is that a malicious HTTP server sends a very long unterminated chunk-size line. The impact is that unbounded memory allocation can exhaust the client process. This issue is fixed in version 2.8.0.

Patch / fix

  • pypi urllib3 2.8.0
  • python urllib3 2.8.0
  • python-urllib3 Debian 14 2.8.0-1

debian advisories DEBIAN-CVE-2026-97689

  • python-urllib3 Ubuntu 22.04 LTS 1.26.5-1~exp1ubuntu0.8
  • python-urllib3 Ubuntu 24.04 LTS 2.0.7-1ubuntu0.8
  • python-urllib3 Ubuntu 26.04 LTS 2.6.3-1ubuntu1.2
  • python-urllib3 Ubuntu Pro 18.04 LTS 1.22-1ubuntu0.18.04.2+esm5
  • python-urllib3 Ubuntu Pro 20.04 LTS 1.25.8-2ubuntu0.4+esm6

ubuntu advisories UBUNTU-CVE-2026-97689

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python3.14-urllib3 RHEL 10.2 2.6.3-2.el10_2.6
  • python3.14-urllib3 RHEL 9 2.6.3-2.el9_8.6
  • python-urllib3 hummingbird 1 2.8.0-1.hum1
  • python3-urllib3 hummingbird 1 2.8.0-1.hum1
  • python3-urllib3+h2 hummingbird 1 2.8.0-1.hum1
  • python3-urllib3+zstd hummingbird 1 2.8.0-1.hum1
  • python3-urllib3+socks hummingbird 1 2.8.0-1.hum1
  • python3-urllib3+brotli hummingbird 1 2.8.0-1.hum1

red hat advisories RHSA-2026:84578RHSA-2026:84577RHSA-2026:69612

  • python-urllib3_1 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Python 3 15 SP7 1.26.18-150600.3.14.1
  • python-urllib3 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +9 more 2.0.7-150400.7.36.1
  • python-urllib3 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +11 more 1.25.10-150300.4.33.1
  • python-urllib3 SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS, SLE Module for Public Cloud 12 1.25.10-3.54.1
  • python-urllib3 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 2.5.0-160000.8.1

suse advisories SUSE-SU-2026:4948-1SUSE-SU-2026:4704-1SUSE-SU-2026:4650-1SUSE-SU-2026:4649-1SUSE-SU-2026:24125-1SUSE-SU-2026:24217-1

  • python-urllib3_1 openSUSE Leap 16.0 1.26.20-160000.5.1
  • python-urllib3_1 openSUSE Tumbleweed 1.26.20-8.1
  • python-urllib3 openSUSE Leap 16.0 2.5.0-160000.8.1
  • python-urllib3 openSUSE Tumbleweed 2.8.0-1.1

opensuse advisories openSUSE-SU-2026:22252-1openSUSE-SU-2026:12119-1openSUSE-SU-2026:22071-1openSUSE-SU-2026:12044-1

  • python3.12-urllib3 AlmaLinux 8 1.26.19-5.el8_10
  • python3-urllib3 AlmaLinux 8 1.24.2-11.el8_10
  • python3-urllib3 AlmaLinux 9 1.26.5-8.el9_8.2
  • python3.12-urllib3 AlmaLinux 9 1.26.19-3.el9_8.2
  • python3-urllib3 AlmaLinux 10 1.26.19-4.el10_2.2
  • python3.14-urllib3 AlmaLinux 9 2.6.3-2.el9_8.6
  • python3.14-urllib3 AlmaLinux 10 2.6.3-2.el10_2.6

almalinux advisories ALSA-2026:92474ALSA-2026:90759ALSA-2026:90494ALSA-2026:85929ALSA-2026:85930ALSA-2026:84577

  • python-urllib3 Rocky Linux 10 1.26.19-4.el10_2.2
  • python3.12-urllib3 Rocky Linux 8 1.26.19-5.el8_10
  • python-urllib3 Rocky Linux 9 1.26.5-8.el9_8.2
  • python-urllib3 Rocky Linux 8 1.24.2-11.el8_10
  • python3.12-urllib3 Rocky Linux 9 1.26.19-3.el9_8.2
  • python3.14-urllib3 Rocky Linux 10 2.6.3-2.el10_2.6
  • python3.14-urllib3 Rocky Linux 9 2.6.3-2.el9_8.6

rocky linux advisories RLSA-2026:85930RLSA-2026:92474RLSA-2026:90494RLSA-2026:90759RLSA-2026:85929RLSA-2026:84578

  • python-urllib3 Azure Linux 3.0 2.0.7-7

azure linux advisories AZL-105660

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-97689 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-2026-97689 updated cvss 7.5

urllib3: urllib3: Denial of Service via unbounded memory allocation in chunk parser

  • Red Hat Ansible Automation Orchestrator 2026 ansible-automation-platform/automation-orchestrator-backend-rhel9 Red Hat Lightspeed Core lightspeed-core/rag-tool-cpu-rhel9, lightspeed-core/lightspeed-stack-rhel9, lightspeed-core/rag-tool-cuda-12.9-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-rhel9-operator, mta/mta-solution-server-rhel9 Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-rhel8-operator Red Hat Migration Toolkit for Virtualization migration-toolkit-virtualization/mtv-rhel9-operator Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9, openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9, openshift-lightspeed/lightspeed-to-dataverse-exporter-rhel9
    affected: no fix available
  • Red Hat AI Inference Server rhaii/vllm-tpu-rhel9, rhaiis/vllm-tpu-rhel9, rhaiis/vllm-cuda-rhel9, rhaiis/vllm-rocm-rhel9, rhaii/vllm-neuron-rhel9, rhaiis/vllm-spyre-rhel9, +1 more
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat Ansible Automation Platform 2 python-urllib3, python3x-urllib3, python3.11-urllib3, python3.12-urllib3, automation-controller, ansible-automation-platform-24/hub-rhel8, +59 more
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-gaudi-rhel9 Red Hat OpenShift AI (RHOAI) rhai/guidellm-rhel9, rhoai/odh-automl-rhel9, rhoai/odh-mlflow-rhel9, rhoai/odh-autorag-rhel9, rhoai/odh-ogx-core-rhel9, rhoai/odh-caikit-nlp-rhel9, +43 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-9, openshift4/ose-ironic-rhel9, openshift4/ose-ironic-agent-rhel9, openshift4/ose-ansible-rhel9-operator Red Hat OpenShift Container Platform 5 openshift5/ose-ironic-rhel9, openshift5/ose-ironic-agent-rhel9, openshift5/ose-ansible-rhel9-operator Red Hat OpenShift Virtualization 4 container-native-virtualization/ocp-virt-validation-checkup-rhel9 Red Hat OpenStack Platform 13 (Queens) python2-urllib3
    +4 more products
    Red Hat OpenStack Platform 17.1 python-urllib3 Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9 Red Hat Satellite 6 satellite/iop-vmaas-rhel9, satellite/iop-puptoo-rhel9, satellite/iop-yuptoo-rhel9, satellite/iop-advisor-engine-rhel9, satellite/iop-host-inventory-rhel9, satellite/iop-advisor-backend-rhel9, +2 more Red Hat Self-service automation portal 2 ansible-automation-platform/bootc-automation-portal-rhel9
    affected: no fix available
  • Red Hat Exploit Intelligence exploit-intelligence/vulnerability-analysis-rhel9
    under investigation
  • Red Hat AI Inference Server 3.4 rhaii/vllm-cpu-rhel9 1791857301, rhaii/vllm-cuda-rhel9 1791857183, rhaii/vllm-rocm-rhel9 1791856725, rhaii/vllm-spyre-rhel9 1791858592, rhaii/model-opt-cuda-rhel9 1791857110
    fixed: vendor fix RHSA-2026:83116
  • Red Hat AI Inference Server 3.5 rhaii/vllm-cpu-rhel9 1791473614, rhaii/vllm-cuda-rhel9 1791473631, rhaii/vllm-rocm-rhel9 1791425869, rhaii/vllm-gaudi-rhel9 1791427182, rhaii/vllm-spyre-rhel9 1791818357
    fixed: vendor fix RHSA-2026:82415
  • Red Hat Ansible Automation Platform 2.6 ansible-automation-platform-26/lightspeed-rhel9 1791898403, ansible-automation-platform-26/lightspeed-chatbot-rhel9 1791978798
    fixed: vendor fix RHSA-2026:87120
show 18 more
  • Red Hat Ansible Automation Platform 2.7 ansible-automation-platform-27/hub-rhel9 1792388670, ansible-automation-platform-27/lightspeed-rhel9 1792141386, ansible-automation-platform-27/hub-rhel9-operator 1792138436
    fixed: vendor fix RHSA-2026:87124
  • Red Hat Cost Management On-Premise 1 costmanagement/costmanagement-ui-rhel10 1793825318
    fixed: vendor fix RHSA-2026:95365
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 1793733716
    fixed: vendor fix RHSA-2026:94802
  • Red Hat Enterprise Linux AI 3.4 rhelai3/bootc-cuda-rhel9 1792612985, rhelai3/bootc-rocm-rhel9 1792612921, rhelai3/bootc-aws-cuda-rhel9 1792680701, rhelai3/bootc-gcp-cuda-rhel9 1792680694, rhelai3/disk-image-cuda-rhel9 1792701796, rhelai3/bootc-azure-cuda-rhel9 1792680694, +1 more
    fixed: vendor fix RHSA-2026:90440
  • Red Hat Enterprise Linux AI 3.5 rhelai3/bootc-cuda-rhel9 1793135861, rhelai3/bootc-rocm-rhel9 1793135863, rhelai3/bootc-aws-cuda-rhel9 1793194817, rhelai3/bootc-gcp-cuda-rhel9 1793194815, rhelai3/disk-image-cuda-rhel9 1793206758, rhelai3/bootc-azure-cuda-rhel9 1793194815, +1 more
    fixed: vendor fix RHSA-2026:92452
  • Red Hat Enterprise Linux AppStream (v. 8) python3.12-urllib3 1.26.19-5.el8_10
    fixed: vendor fix RHSA-2026:92474
  • Red Hat Enterprise Linux AppStream (v. 9) python3.14-urllib3 2.6.3-2.el9_8.6, python3.12-urllib3 1.26.19-3.el9_8.2
    fixed: vendor fix RHSA-2026:85929
  • Red Hat Enterprise Linux AppStream (v. 10) python3.14-urllib3 2.6.3-2.el10_2.6
    fixed: vendor fix RHSA-2026:84578
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) python3.12-urllib3 1.26.18-2.el9_4.3
    fixed: vendor fix RHSA-2026:98097
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) python3.12-urllib3 1.26.19-1.el9_6.2
    fixed: vendor fix RHSA-2026:98098
  • Red Hat Enterprise Linux BaseOS (v. 8) python-urllib3 1.24.2-11.el8_10, python3-urllib3 1.24.2-11.el8_10
    fixed: vendor fix RHSA-2026:90759
  • Red Hat Enterprise Linux BaseOS (v. 9) python-urllib3 1.26.5-8.el9_8.2, python3-urllib3 1.26.5-8.el9_8.2
    fixed: vendor fix RHSA-2026:90494
  • Red Hat Enterprise Linux BaseOS (v. 10) python-urllib3 1.26.19-4.el10_2.2, python3-urllib3 1.26.19-4.el10_2.2
    fixed: vendor fix RHSA-2026:85930
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) python-urllib3 1.26.5-3.el9_2.5, python3-urllib3 1.26.5-3.el9_2.5
    fixed: vendor fix RHSA-2026:98126
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) python-urllib3 1.26.5-5.el9_4.5, python3-urllib3 1.26.5-5.el9_4.5
    fixed: vendor fix RHSA-2026:98125
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) python-urllib3 1.26.19-2.el10_0.2, python3-urllib3 1.26.19-2.el10_0.2
    fixed: vendor fix RHSA-2026:98096
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) python-urllib3 1.26.5-6.el9_6.3, python3-urllib3 1.26.5-6.el9_6.3
    fixed: vendor fix RHSA-2026:98122
  • Red Hat Hardened Images python-urllib3 2.8.0-1.hum1, python3-urllib3 2.8.0-1.hum1, python3-urllib3+h2 2.8.0-1.hum1, python3-urllib3+zstd 2.8.0-1.hum1, python3-urllib3+socks 2.8.0-1.hum1, python3-urllib3+brotli 2.8.0-1.hum1
    fixed: vendor fix RHSA-2026:69612

10 more fixed, 31 more not affected in the full advisory

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
last mo.

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 8.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
CNA 4.0 8.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:X/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

Affected packages

ecosystem package affected fixed in
pypi urllib3
>=1.10.3, <2.8.0
2.8.0

Affected products

  • urllib3 urllib3

Classification

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

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 urllib3/urllib3 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.