CVE-2026-103262
Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClient
02 Description
Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClient
03 Exploitation and scoring
- Exploitation
- Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
- SSVC decision
- ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.62% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 49.7% of scored records. A rank, not a probability.
- NVD base score
- 8.7 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- 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
- NVD analysis status
- Deferred. NVD last modified this record on 2026-10-06.
- Red Hat severity
- Important. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-10-01 10:42Z28 DAYS AGO
- Last updated
- 2026-10-06 00:08Z23 DAYS AGO
- Reserved
- 2026-09-30
- Assigning CNA
- VulnCheck
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.7)
- CNA CVSS vector
- 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
- Weaknesses
- CWE-409Improper Handling of Highly Compressed Data (Data Amplification)Base
- Data version
- 5.2
- Document digest
- a83332579c1ce455718f50ec852012535eb0572ab9d3248cca7e5af3e4a461f2
05 Affected products
06 References
- github.comGitHub Security Advisory (GHSA-chx6-46f5-w4vp)https://github.com/tornadoweb/tornado/security/advisories/GHSA-chx6-46f5-w4vp
- github.comhttps://github.com/tornadoweb/tornado/commit/e412435febba4569c552c5c9054f1bf92bd171a9
- www.vulncheck.comVulnCheck Advisory: Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClienthttps://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-curlasynchttpclient
07 Fixed in
AlmaLinux 9
- python3-tornado Fixed in 6.5.10-1.el9_8.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
AlmaLinux 10
- python3-tornado Fixed in 6.5.10-1.el10_2.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 9
- python3-tornado Fixed in 6.5.10-1.el9_8.1
Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 10
- python3-tornado Fixed in 6.5.10-1.el10_2.1
Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- python-tornado No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- python-tornado No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- python-tornado No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 24.04 LTS
- python-tornado Fixed in 6.4.0-1ubuntu0.6
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 26.04 LTS
- python-tornado Fixed in 6.5.4-0.1ubuntu0.2
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 16.04 LTS
- python-tornado Fixed in 4.2.1-1ubuntu3.1+esm4Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 18.04 LTS
- python-tornado Fixed in 4.5.3-1ubuntu0.2+esm4Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 22.04 LTS
- python-tornado No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.