Detections
Analytics
TencentOS Server 4: python-tornado (TSSA-2025:0977)
medium Nessus Plugin ID 281640
Synopsis
The remote TencentOS Server 4 host is missing one or more security updates.Description
The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2025:0977 advisory.Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:
CVE-2025-67726:
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.count() within a nested loop while processing quoted semicolons. If an attacker sends a request with a large number of maliciously crafted parameters in a Content-Disposition header, the server's CPU usage increases quadratically (O(n)) during parsing. Due to Tornado's single event loop architecture, a single malicious request can cause the entire server to become unresponsive for an extended period. This issue is fixed in version 6.5.3.
CVE-2025-67725:
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 of Service (DoS). Due to Python string immutability, each concatenation copies the entire string, resulting in O(n) time complexity. The severity can vary from high if max_header_size has been increased from its default, to low if it has its default value of 64KB.
This issue is fixed in version 6.5.3.
CVE-2025-67724:
Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, the supplied reason phrase is used unescaped in HTTP headers (where it could be used for header injection) or in HTML in the default error page (where it could be used for XSS) and can be exploited by passing untrusted or malicious data into the reason argument. Used by both RequestHandler.set_status and tornado.web.HTTPError, the argument is designed to allow applications to pass custom reason phrases (the Not Found in HTTP/1.1 404 Not Found) to the HTTP status line (mainly for non-standard status codes).
This issue is fixed in version 6.5.3.
Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Solution
Update the affected packages.See Also
Plugin Details
Severity: Medium
ID: 281640
File Name: tencentos_TSSA_2025_0977.nasl
Version: 1.1
Type: local
Family: Tencent Local Security Checks
Published: 1/4/2026
Updated: 1/4/2026
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 4.4
CVSS v2
Risk Factor: Medium
Base Score: 6.4
Temporal Score: 4.7
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N
CVSS Score Source: CVE-2025-67724
CVSS v3
Risk Factor: Medium
Base Score: 6.1
Temporal Score: 5.3
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
CPE: p-cpe:/a:tencent:tencentos_server:python-tornado, cpe:/o:tencent:tencentos_server:4
Required KB Items: Host/local_checks_enabled, Host/cpu, Host/etc/os-release, Host/TencentOS/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 12/30/2025
Vulnerability Publication Date: 12/12/2025