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Fencer Intel
high 7.5

CVE-2026-103262 json

Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClient

published last mo. modified last mo. also EUVD-2026-90656 , GHSA-chx6-46f5-w4vp

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

Tornado versions before 6.5.9 contain an unbounded memory accumulation vulnerability in CurlAsyncHTTPClient that allows remote attackers to cause denial of service by sending a compressed response. Attackers can send a gzip-encoded decompression bomb that accumulates in memory without size limits, causing the application process to be killed by out-of-memory conditions.

Patch / fix

  • pypi tornado 6.5.9
  • tornadoweb tornado 6.5.9
  • python-tornado Ubuntu 24.04 LTS 6.4.0-1ubuntu0.6
  • python-tornado Ubuntu 26.04 LTS 6.5.4-0.1ubuntu0.2
  • python-tornado Ubuntu Pro 16.04 LTS 4.2.1-1ubuntu3.1+esm4
  • python-tornado Ubuntu Pro 18.04 LTS 4.5.3-1ubuntu0.2+esm4

ubuntu advisories UBUNTU-CVE-2026-103262

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

  • python-tornado RHEL 10.2 6.5.10-1.el10_2.1
  • python3-tornado RHEL 10.2 6.5.10-1.el10_2.1
  • python-tornado RHEL 9 6.5.10-1.el9_8.1
  • python3-tornado RHEL 9 6.5.10-1.el9_8.1

red hat advisories RHSA-2026:82041RHSA-2026:82040

  • python3-tornado AlmaLinux 9 6.5.10-1.el9_8.1
  • python3-tornado AlmaLinux 10 6.5.10-1.el10_2.1

almalinux advisories ALSA-2026:82040ALSA-2026:82041

  • python-tornado Rocky Linux 10 6.5.10-1.el10_2.1
  • python-tornado Rocky Linux 9 6.5.10-1.el9_8.1

rocky linux advisories RLSA-2026:82041RLSA-2026:82040

Is CVE-2026-103262 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.

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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-2026-103262 updated cvss 7.5

tornado: Tornado: Denial of Service via decompression bomb in CurlAsyncHTTPClient

  • Red Hat Lightspeed Core lightspeed-core/rag-tool-cpu-rhel9, lightspeed-core/lightspeed-stack-rhel9, lightspeed-core/rag-tool-cuda-12.9-rhel9
    affected: workaround, no fix available
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/disk-image-cuda-rhel9
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-llama-stack-core-rhel9, rhoai/odh-pipeline-runtime-minimal-cpu-py312-rhel9, rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9, rhoai/odh-workbench-jupyter-minimal-cpu-py312-rhel9, rhoai/odh-workbench-jupyter-minimal-cuda-py312-rhel9, +13 more Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9 Red Hat OpenStack Platform 16.2 rhosp-rhel8/openstack-redis, rhosp-rhel8/openstack-haproxy, rhosp-rhel8/openstack-mariadb, rhosp-rhel8/openstack-rabbitmq, rhosp-rhel8/openstack-ovn-northd, rhosp-rhel8/openstack-manila-share, +2 more Red Hat OpenStack Platform 17.1 rhosp-rhel9/openstack-redis, rhosp-rhel9/openstack-haproxy, rhosp-rhel9/openstack-mariadb, rhosp-rhel9/openstack-rabbitmq, rhosp-rhel9/openstack-ovn-northd, rhosp-rhel9/openstack-manila-share, +2 more
    affected: workaround, no fix available
  • Red Hat Ansible Automation Platform 2.6 ansible-automation-platform-26/lightspeed-chatbot-rhel9 1791978798
    fixed: vendor fix RHSA-2026:87120
  • Red Hat Ansible Automation Platform 2.7 ansible-automation-platform-27/lightspeed-chatbot-rhel9 1792385971
    fixed: vendor fix RHSA-2026:87124
  • Red Hat Enterprise Linux AppStream (v. 9) python-tornado 6.5.10-1.el9_8.1, python3-tornado 6.5.10-1.el9_8.1
    fixed: vendor fix RHSA-2026:82040
  • Red Hat Enterprise Linux AppStream (v. 10) python-tornado 6.5.10-1.el10_2.1, python3-tornado 6.5.10-1.el10_2.1
    fixed: vendor fix RHSA-2026:82041
show 10 more
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) python-tornado 6.5.10-0.el10_0.1, python3-tornado 6.5.10-0.el10_0.1
    fixed: vendor fix RHSA-2026:91583
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) python-tornado 6.4.2-2.el9_6.7, python3-tornado 6.4.2-2.el9_6.7
    fixed: vendor fix RHSA-2026:90283
  • Red Hat OpenShift AI 2.25 rhoai/odh-feature-server-rhel9 1792148523
    fixed: vendor fix RHSA-2026:87410
  • Red Hat OpenShift AI 3.4 rhoai/odh-feature-server-rhel9 1791863220, rhoai/odh-trustyai-nemo-guardrails-server-rhel9 1791556128
    fixed: vendor fix RHSA-2026:84734
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202610241758
    fixed: vendor fix RHSA-2026:89197
  • Red Hat Migration Toolkit for Applications 8 mta/mta-solution-server-rhel9 Red Hat Ansible Automation Platform 2.6 ansible-automation-platform-26/hub-rhel9 1791947385, ansible-automation-platform-26/gateway-rhel9 1791971533, ansible-automation-platform-26/hub-web-rhel9 1791952205, ansible-automation-platform-26/receptor-rhel9 1791968536, ansible-automation-platform-26/mcp-tools-rhel9 1791941340, ansible-automation-platform-26/controller-rhel9 1791947602, +24 more Red Hat Ansible Automation Platform 2.7 ansible-automation-platform-27/hub-rhel9 1792388670, ansible-automation-platform-27/gateway-rhel9 1792429216, ansible-automation-platform-27/hub-web-rhel9 1792394496, ansible-automation-platform-27/receptor-rhel9 1792139928, ansible-automation-platform-27/mcp-tools-rhel9 1792425046, ansible-automation-platform-27/controller-rhel9 1792389457, +26 more
    not affected: vulnerable code not present
  • Red Hat Enterprise Linux 8 pcs, pcs-snmp
    not affected: vulnerable code cannot be controlled by adversary
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-th-torch-cpu-py312-rhel9, rhoai/odh-th-torch-cuda-py312-rhel9, rhoai/odh-th-torch-rocm-py312-rhel9, rhoai/odh-th06-cpu-torch210-py312-rhel9, rhoai/odh-th06-cpu-torch291-py312-rhel9, rhoai/odh-th06-rocm64-torch291-py312-rhel9, +2 more
    not affected: vulnerable code not in execute path
  • 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, +65 more Red Hat OpenShift AI 3.4 rhoai/odh-cli-rhel9 1791509689, rhoai/rhai-cli-rhel9 1791509689, rhoai/odh-automl-rhel9 1791535789, rhoai/odh-mlflow-rhel9 1791865967, rhoai/odh-autorag-rhel9 1791557539, rhoai/odh-trainer-rhel9 1791869783, +98 more
    not affected: vulnerable code not present
  • Red Hat OpenShift Container Platform 4 python-flit 3.9.0-3.1.el9ocp, python-pep517 0.13.0-5.2.el9ocp, python-tornado 6.1.0-3.el9ocp.1
    not affected: component 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
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.63% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/tornadoweb/tornado/security/advisories/GHSA-chx6-46f5-w4vp referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 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
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 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: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

Affected packages

ecosystem package affected fixed in
pypi tornado
<6.5.9
6.5.9

Affected products

  • tornadoweb tornado

Classification

Weakness
  • CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)
  • CWE-400 Uncontrolled Resource Consumption

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.

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