TencentOS Server 3: osbuild-composer (TSSA-2026:0911)

medium Nessus Plugin ID 341108

Synopsis

The remote TencentOS Server 3 host is missing one or more security updates.

Description

The version of Tencent Linux installed on the remote TencentOS Server 3 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:0911 advisory.

Package updates are available for TencentOS Server 3 that fix the following vulnerabilities:

CVE-2026-32280:
During chain building, the amount of work that is done is not correctly limited when a large number of intermediate certificates are passed in VerifyOptions.Intermediates, which can lead to a denial of service. This affects both direct users of crypto/x509 and users of crypto/tls.

CVE-2026-32282:
On Linux, if the target of Root.Chmod is replaced with a symlink while the chmod operation is in progress, Chmod can operate on the target of the symlink, even when the target lies outside the root. The Linux fchmodat syscall silently ignores the AT_SYMLINK_NOFOLLOW flag, which Root.Chmod uses to avoid symlink traversal. Root.Chmod checks its target before acting and returns an error if the target is a symlink lying outside the root, so the impact is limited to cases where the target is replaced with a symlink between the check and operation.

CVE-2026-32283:
If one side of the TLS connection sends multiple key update messages post-handshake in a single record, the connection can deadlock, causing uncontrolled consumption of resources. This can lead to a denial of service. This only affects TLS 1.3.

CVE-2026-33186:
gRPC-Go is the Go language implementation of gRPC. Versions prior to 1.79.3 have an authorization bypass resulting from improper input validation of the HTTP/2 :path pseudo-header. The gRPC-Go server was too lenient in its routing logic, accepting requests where the :path omitted the mandatory leading slash (e.g., Service/Method instead of /Service/Method). While the server successfully routed these requests to the correct handler, authorization interceptors (including the official grpc/authz package) evaluated the raw, non-canonical path string. Consequently, deny rules defined using canonical paths (starting with /) failed to match the incoming request, allowing it to bypass the policy if a fallback allow rule was present. This affects gRPC-Go servers that use path-based authorization interceptors, such as the official RBAC implementation in google.golang.org/grpc/authz or custom interceptors relying on info.FullMethod or grpc.Method(ctx); AND that have a security policy contains specific deny rules for canonical paths but allows other requests by default (a fallback allow rule). The vulnerability is exploitable by an attacker who can send raw HTTP/2 frames with malformed :path headers directly to the gRPC server. The fix in version 1.79.3 ensures that any request with a :path that does not start with a leading slash is immediately rejected with a codes.Unimplemented error, preventing it from reaching authorization interceptors or handlers with a non-canonical path string. While upgrading is the most secure and recommended path, users can mitigate the vulnerability using one of the following methods: Use a validating interceptor (recommended mitigation); infrastructure-level normalization; and/or policy hardening.

CVE-2026-34986:
Go JOSE provides an implementation of the Javascript Object Signing and Encryption set of standards in Go, including support for JSON Web Encryption (JWE), JSON Web Signature (JWS), and JSON Web Token (JWT) standards. Prior to 4.1.4 and 3.0.5, decrypting a JSON Web Encryption (JWE) object will panic if the alg field indicates a key wrapping algorithm (one ending in KW, with the exception of A128GCMKW, A192GCMKW, and A256GCMKW) and the encrypted_key field is empty. The panic happens when cipher.KeyUnwrap() in key_wrap.go attempts to allocate a slice with a zero or negative length based on the length of the encrypted_key. This code path is reachable from ParseEncrypted() / ParseEncryptedJSON() / ParseEncryptedCompact() followed by Decrypt() on the resulting object. Note that the parse functions take a list of accepted key algorithms. If the accepted key algorithms do not include any key wrapping algorithms, parsing will fail and the application will be unaffected. This panic is also reachable by calling cipher.KeyUnwrap() directly with any ciphertext parameter less than 16 bytes long, but calling this function directly is less common. Panics can lead to denial of service. This vulnerability is fixed in 4.1.4 and 3.0.5.

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

https://mirrors.tencent.com/tlinux/errata/tssa-20260911.xml

Plugin Details

Severity: Medium

ID: 341108

File Name: tencentos_TSSA_2026_0911.nasl

Version: 1.1

Type: Local

Published: 8/27/2026

Updated: 8/27/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.3

Percentile: 96.6

CVSS v2

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 4.6

Vector: CVSS2#AV:L/AC:H/Au:M/C:C/I:C/A:C

CVSS Score Source: CVE-2026-32282

CVSS v3

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.8

Vector: CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:tencent:tencentos_server:3, p-cpe:/a:tencent:tencentos_server:osbuild-composer

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/etc/os-release, Host/TencentOS/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/31/2026

Vulnerability Publication Date: 3/18/2026

Reference Information

CVE: CVE-2026-32280, CVE-2026-32282, CVE-2026-32283, CVE-2026-33186, CVE-2026-34986