Staging Environment: Content and features may be unstable or change without notice.
Search for vulnerabilities
Vulnerability details: VCID-jf6j-dngc-6qdp
Vulnerability ID VCID-jf6j-dngc-6qdp
Aliases GHSA-qppv-j76h-2rpx
GMS-2023-1908
Summary Tornado vulnerable to HTTP request smuggling via improper parsing of `Content-Length` fields and chunk lengths ## Summary Tornado interprets `-`, `+`, and `_` in chunk length and `Content-Length` values, which are not allowed by the HTTP RFCs. This can result in request smuggling when Tornado is deployed behind certain proxies that interpret those non-standard characters differently. This is known to apply to older versions of haproxy, although the current release is not affected. ## Details Tornado uses the `int` constructor to parse the values of `Content-Length` headers and chunk lengths in the following locations: ### `tornado/http1connection.py:445` ```python3 self._expected_content_remaining = int(headers["Content-Length"]) ``` ### `tornado/http1connection.py:621` ```python3 content_length = int(headers["Content-Length"]) # type: Optional[int] ``` ### `tornado/http1connection.py:671` ```python3 chunk_len = int(chunk_len_str.strip(), 16) ``` Because `int("0_0") == int("+0") == int("-0") == int("0")`, using the `int` constructor to parse and validate strings that should contain only ASCII digits is not a good strategy.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
System Score Found at
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-qppv-j76h-2rpx
generic_textual MODERATE https://github.com/tornadoweb/tornado
generic_textual MODERATE https://github.com/tornadoweb/tornado/commit/b7a5dd29bb02950303ae96055082c12a1ea0a4fe
cvssv3.1_qr MODERATE https://github.com/tornadoweb/tornado/security/advisories/GHSA-qppv-j76h-2rpx
generic_textual MODERATE https://github.com/tornadoweb/tornado/security/advisories/GHSA-qppv-j76h-2rpx
Reference id Reference type URL
https://github.com/tornadoweb/tornado
https://github.com/tornadoweb/tornado/commit/b7a5dd29bb02950303ae96055082c12a1ea0a4fe
GHSA-qppv-j76h-2rpx https://github.com/advisories/GHSA-qppv-j76h-2rpx
GHSA-qppv-j76h-2rpx https://github.com/tornadoweb/tornado/security/advisories/GHSA-qppv-j76h-2rpx
No exploits are available.

No EPSS data available for this vulnerability.

Date Actor Action Source VulnerableCode Version
2026-04-01T12:51:41.724258+00:00 GitLab Importer Import https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/tornado/GMS-2023-1908.yml 38.0.0