Tornadoweb Tornado vulnerabilities

CVE-2023-54397 [HIGH] CWE-444 CVE-2023-54397: Tornado before 6.3.3 contains an HTTP request smuggling vulnerability due to improper parsing of Con Tornado before 6.3.3 contains an HTTP request smuggling vulnerability due to improper parsing of Content-Length headers accepting non-standard characters. Attackers can send crafted HTTP requests with these characters to bypass proxy validation and smuggle requests when deployed behind certain proxies.

CVE-2024-14029 [HIGH] CWE-444 CVE-2024-14029: Tornado before 6.4.1 ignores duplicate Transfer-Encoding: chunked headers, treating requests as havi Tornado before 6.4.1 ignores duplicate Transfer-Encoding: chunked headers, treating requests as having no message body and parsing the chunked body as a subsequent request. Attackers can exploit this inconsistency when Tornado is deployed behind proxies to perform HTTP request smuggling, enabling access control bypass, cache poisoning, or connection d

CVE-2026-49853 [HIGH] CWE-200 CVE-2026-49853: Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, SimpleAsyncHT Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, SimpleAsyncHTTPClient shallow-copied redirected requests and removed only the Host header, leaving Authorization, auth_username, auth_password, and auth_mode in place when a redirect changed scheme, host, or port. This issue is fixed in version 6.5.6.

CVE-2025-47287 [HIGH] CWE-770 CVE-2025-47287: Tornado is a Python web framework and asynchronous networking library. When Tornado's ``multipart/fo Tornado is a Python web framework and asynchronous networking library. When Tornado's ``multipart/form-data`` parser encounters certain errors, it logs a warning but continues trying to parse the remainder of the data. This allows remote attackers to generate an extremely high volume of logs, constituting a DoS attack. This DoS is compounded by the fa

CVE-2025-67725 [HIGH] CWE-400 CVE-2025-67725: Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, a single maliciously crafted HTTP request can block the server's event loop for an extended period, caused by the HTTPHeaders.add method. The function accumulates values using string concatenation when the same header name is repeated, causing a Denial o

CVE-2025-67726 [HIGH] CWE-400 CVE-2025-67726: Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The _parseparam function in httputil.py is used to parse specific HTTP header values, such as those in multipart/form-data and repeatedly calls string.cou

CVE-2026-49855 [HIGH] CWE-409 CVE-2026-49855: Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, Tornado gzip Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, Tornado gzip decompression routines processed limited-size chunks but did not enforce an overall limit on accumulated decompressed chunks, allowing a malicious server accessed by SimpleAsyncHTTPClient or an HTTPServer configured with decompress_request=True to consum

CVE-2026-31958 [HIGH] CWE-400 CVE-2026-31958: Tornado is a Python web framework and asynchronous networking library. In versions of Tornado prior Tornado is a Python web framework and asynchronous networking library. In versions of Tornado prior to 6.5.5, the only limit on the number of parts in multipart/form-data is the max_body_size setting (default 100MB). Since parsing occurs synchronously on the main thread, this creates the possibility of denial-of-service due to the cost of parsing very

CVE-2026-82397 [HIGH] CWE-400 CVE-2026-82397: Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.8, Tornado parse Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.8, Tornado parses application/x-www-form-urlencoded request bodies with urllib.parse.parse_qs in tornado/escape.py without passing max_num_fields. RequestHandler._execute in tornado/web.py parses the body before handler dispatch through HTTPServerRequest._parse_body an

CVE-2026-103262 [HIGH] CWE-409 CVE-2026-103262: Tornado versions before 6.5.9 contain an unbounded memory accumulation vulnerability in CurlAsyncHTT 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-

CVE-2026-91990 [HIGH] CWE-770 CVE-2026-91990: Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit. Attackers can send crafted multipart requests with many parts to create large transient lists, exhausting server memory and causing denial of service.

CVE-2026-103263 [MEDIUM] CWE-59 CVE-2026-103263: Tornado before 6.5.9 contains a path traversal vulnerability in StaticFileHandler that follows symbo Tornado before 6.5.9 contains a path traversal vulnerability in StaticFileHandler that follows symbolic links inside the static root without confirming the resolved target stays within it. When a symlink pointing outside the static directory exists inside it, unauthenticated attackers can request it to read files such as configuration files, privat

CVE-2024-52804 [HIGH] CWE-400 CVE-2024-52804: Tornado is a Python web framework and asynchronous networking library. The algorithm used for parsin Tornado is a Python web framework and asynchronous networking library. The algorithm used for parsing HTTP cookies in Tornado versions prior to 6.4.2 sometimes has quadratic complexity, leading to excessive CPU consumption when parsing maliciously-crafted cookie headers. This parsing occurs in the event loop thread and may block the processing of othe

CVE-2014-9720 [MEDIUM] CWE-203 CVE-2014-9720: Tornado before 3.2.2 sends arbitrary responses that contain a fixed CSRF token and may be sent with Tornado before 3.2.2 sends arbitrary responses that contain a fixed CSRF token and may be sent with HTTP compression, which makes it easier for remote attackers to conduct a BREACH attack and determine this token via a series of crafted requests.

CVE-2026-91992 [MEDIUM] CWE-200 CVE-2026-91992: Tornado before 6.5.7 contains a credential leak vulnerability in CurlAsyncHTTPClient where pycurl ha Tornado before 6.5.7 contains a credential leak vulnerability in CurlAsyncHTTPClient where pycurl handles are reused across requests without proper state clearing. Attackers can obtain sensitive credentials by issuing requests through the same client instance, allowing TLS certificates or proxy authentication to persist across unintended requests.

CVE-2026-103261 [MEDIUM] CWE-770 CVE-2026-103261: Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, 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 sharin

CVE-2026-91991 [MEDIUM] CWE-113 CVE-2026-91991: Tornado before 6.5.8 contains an incomplete fix for cookie attribute injection that allows attackers Tornado before 6.5.8 contains an incomplete fix for cookie attribute injection that allows attackers to inject arbitrary cookie attributes by passing capitalized or legacy keyword arguments to set_cookie. Attackers can embed semicolon-delimited data in capitalized parameters like Domain, Path, or SameSite to bypass validation and modify cookie secur

CVE-2024-58384 [MEDIUM] CWE-113 CVE-2024-58384: Tornado before 6.4.1 contains a CRLF injection vulnerability in CurlAsyncHTTPClient that fails to re Tornado before 6.4.1 contains a CRLF injection vulnerability in CurlAsyncHTTPClient that fails to reject carriage return and line feed characters in request headers. Attackers can inject CRLF sequences into header values to inject arbitrary headers or construct entirely new HTTP requests.

CVE-2023-28370 [MEDIUM] CWE-601 CVE-2023-28370: Open redirect vulnerability in Tornado versions 6.3.1 and earlier allows a remote unauthenticated at Open redirect vulnerability in Tornado versions 6.3.1 and earlier allows a remote unauthenticated attacker to redirect a user to an arbitrary web site and conduct a phishing attack by having user access a specially crafted URL.

CVE-2026-49854 [MEDIUM] CWE-126 CVE-2026-49854: Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, the optional Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, the optional native extension tornado.speedups implemented websocket_mask without validating that the mask argument is exactly four bytes, allowing the C function to read up to three bytes beyond the provided buffer when reached through Tornado XSRF token decoding