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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
tornadoweb tornado unaffected
Version Status Constraints
0 affected < 6.5.9
6.5.9 unaffected —

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Project Subscriptions

Vendors Products
Tornadoweb Subscribe
Tornado Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/tornadoweb/tornado/commit/e412435febba4569c552c5c9054f1bf92bd171a9 cve-icon cve-icon
https://github.com/tornadoweb/tornado/security/advisories/GHSA-chx6-46f5-w4vp cve-icon cve-icon
https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-curlasynchttpclient cve-icon cve-icon
History

Thu, 01 Oct 2026 11:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClient
First Time appeared Tornadoweb
Tornadoweb tornado
Weaknesses CWE-409
CPEs cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:*
Vendors & Products Tornadoweb
Tornadoweb tornado
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, '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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-01T10:42:04.913Z

Reserved: 2026-09-30T10:55:39.869Z

Link: CVE-2026-103262

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-01T11:17:21.050

Modified: 2026-10-01T11:17:21.177

Link: CVE-2026-103262

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses