CVE-2026-103262

Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClient

State: Published
Severity: 8.7 High
Published: Oct 1, 2026
Updated: Oct 6, 2026
Reserved: Sep 30, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	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	VulnCheck
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	VulnCheck

Weaknesses

CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)

Affected Products

Product	Versions
tornadotornadoweb	before 6.5.9Affected 6.5.9Not affected

References

GitHub Security Advisory (GHSA-chx6-46f5-w4vp)vendor-advisory
https://github.com/tornadoweb/tornado/commit/e412435febba4569c552c5c9054f1bf92bd171a9patch
VulnCheck Advisory: Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClientthird-party-advisory

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.