TencentOS Server 4: grpc (TSSA-2025:0125)

high Nessus Plugin ID 238721

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 a vulnerability as referenced in the TSSA-2025:0125 advisory.

Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

CVE-2023-33953:
gRPC contains a vulnerability that allows hpack table accounting errors could lead to unwanted disconnects between clients and servers in exceptional cases/Three vectors were found that allow the following DOS attacks:

- Unbounded memory buffering in the HPACK parser
- Unbounded CPU consumption in the HPACK parser

The unbounded CPU consumption is down to a copy that occurred per-input-block in the parser, and because that could be unbounded due to the memory copy bug we end up with an O(n^2) parsing loop, with n selected by the client.

The unbounded memory buffering bugs:

- The header size limit check was behind the string reading code, so we needed to first buffer up to a 4 gigabyte string before rejecting it as longer than 8 or 16kb.
- HPACK varints have an encoding quirk whereby an infinite number of 0's can be added at the start of an integer. gRPC's hpack parser needed to read all of them before concluding a parse.
- gRPC's metadata overflow check was performed per frame, so that the following sequence of frames could cause infinite buffering: HEADERS: containing a: 1 CONTINUATION: containing a: 2 CONTINUATION: containing a: 3 etc

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

Plugin Details

Severity: High

ID: 238721

File Name: tencentos_TSSA_2025_0125.nasl

Version: 1.1

Type: local

Family: Tencent Local Security Checks

Published: 6/16/2025

Updated: 6/16/2025

Supported Sensors: Nessus

Vulnerability Information

CPE: p-cpe:/a:tencent:tencentos_server:grpc, 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: 2/12/2025

Vulnerability Publication Date: 2/12/2025

Detections

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