High severity · published Oct 1, 2026
CVE-2026-103262
Tornado before 6.5.9 Denial of Service via CurlAsyncHTTPClient
7.5
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 50% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TO
tornado · tornadoweb
before 6.5.9 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-103262
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-103262
vendor-advisory
https://github.com/tornadoweb/tornado/security/advisories/GHSA-chx6-46f5-w4vp
patch
https://github.com/tornadoweb/tornado/commit/e412435febba4569c552c5c9054f1bf92bd171a9
third-party-advisory
https://www.vulncheck.com/advisories/tornado-before-6.5.9-denial-of-service-via-curlasynchttpclient
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