CVE-2026-103261
published 2026-10-01CVE-2026-103261: Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by…
PriorityP433medium5.3CVSS 3.1
AVNACLPRNUINSUCNINAL
EPSS
0.47%
39.5th percentile
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.
Affected
64 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| ansible-automation-platform-26 | lightspeed-chatbot-rhel9 | — | — |
| ansible-automation-platform-27 | lightspeed-chatbot-rhel9 | — | — |
| clusterlabs | pcs | — | — |
| debian | python-tornado | — | — |
| lightspeed-core | lightspeed-stack-rhel9 | — | — |
| lightspeed-core | rag-tool-cpu-rhel9 | — | — |
| lightspeed-core | rag-tool-cuda-12.9-rhel9 | — | — |
| mta | mta-solution-server-rhel9 | — | — |
| openshift-lightspeed | lightspeed-ocp-rag-rhel9 | — | — |
| openshift | ose-rhel-coreos-9 | — | — |
| rhel10 | keylime-registrar | — | — |
| rhel10 | keylime-verifier | — | — |
| rhel9 | keylime-registrar | — | — |
| rhel9 | keylime-verifier | — | — |
| rhelai3 | bootc-cuda-rhel9 | — | — |
| rhelai3 | bootc-gaudi-rhel9 | — | — |
| rhelai3 | bootc-rocm-rhel9 | — | — |
| rhelai3 | disk-image-cuda-rhel9 | — | — |
| rhoai | odh-feature-server-rhel9 | — | — |
| rhoai | odh-llama-stack-core-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-datascience-cpu-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-minimal-cpu-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-pytorch-cuda-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-pytorch-llmcompressor-cuda-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-pytorch-rocm-py312-rhel9 | — | — |
CVSS provenance
nvdv3.15.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
nvdv4.06.9MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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
vendor_redhat5.3MEDIUM
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Red Hat
tornado: tornado: Denial of Service (DoS) via unbounded query string parsing
vendor_redhat·2026-10-01·CVSS 5.3
CVE-2026-103261 [MEDIUM] CWE-770 tornado: tornado: Denial of Service (DoS) via unbounded query string parsing
tornado: tornado: Denial of Service (DoS) via unbounded query string parsing
A flaw was found in Tornado. When processing incoming HTTP requests, Tornado fails to restrict the number of parameters parsed from the URL query string. A remote, unauthenticated attacker could exploit this flaw by sending requests with an excessive number of query parameters, leading to high CPU consumption that stalls the application's event loop. This results in a Denial of Service (DoS), significantly degrading response times for all clients sharing the same server process.
Package: lightspeed-core/lightspeed-stack-rhel9 (Lightspeed Core) - Fix deferred
Package: lightspeed-core/rag-tool-cpu-rhel9 (Lightspeed Core) - Fix deferred
Package: lightspeed-core/rag-tool-cuda-12.9-rhel9 (Lightspeed Core) - Fix def
GHSA
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query
ghsa_unreviewed·2026-10-01
CVE-2026-103261 [MEDIUM] CWE-770 Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-103261 python-pep517: tornado: Denial of Service (DoS) via unbounded query string parsing [epel-all]
bugzilla·2026-10-21·CVSS 5.3
CVE-2026-103261 [MEDIUM] CVE-2026-103261 python-pep517: tornado: Denial of Service (DoS) via unbounded query string parsing [epel-all]
CVE-2026-103261 python-pep517: tornado: Denial of Service (DoS) via unbounded query string parsing [epel-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.
Bugzilla
CVE-2026-103261 python-flit: tornado: Denial of Service (DoS) via unbounded query string parsing [fedora-all]
bugzilla·2026-10-21·CVSS 5.3
CVE-2026-103261 [MEDIUM] CVE-2026-103261 python-flit: tornado: Denial of Service (DoS) via unbounded query string parsing [fedora-all]
CVE-2026-103261 python-flit: tornado: Denial of Service (DoS) via unbounded query string parsing [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.
Bugzilla
CVE-2026-103261 python-flit: tornado: Denial of Service (DoS) via unbounded query string parsing [epel-all]
bugzilla·2026-10-21·CVSS 5.3
CVE-2026-103261 [MEDIUM] CVE-2026-103261 python-flit: tornado: Denial of Service (DoS) via unbounded query string parsing [epel-all]
CVE-2026-103261 python-flit: tornado: Denial of Service (DoS) via unbounded query string parsing [epel-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.
Bugzilla
CVE-2026-103261 tornado: tornado: Denial of Service (DoS) via unbounded query string parsing
bugzilla·2026-10-01·CVSS 5.3
CVE-2026-103261 [MEDIUM] CVE-2026-103261 tornado: tornado: Denial of Service (DoS) via unbounded query string parsing
CVE-2026-103261 tornado: tornado: Denial of Service (DoS) via unbounded query string parsing
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.
2026-10-01
Published