CentOS 9 : gnutls-3.8.10-4.el9

medium Nessus Plugin ID 312106

Synopsis

The remote CentOS host is missing one or more security updates for gnutls.

Description

The remote CentOS Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the gnutls-3.8.10-4.el9 build changelog.

- A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure. (CVE-2026-3833)

- A flaw was found in the GnuTLS library, specifically in the gnutls_pkcs11_token_init() function that handles PKCS#11 token initialization. When a token label longer than expected is processed, the function writes past the end of a fixed-size stack buffer. This programming error can cause the application using GnuTLS to crash or, in certain conditions, be exploited for code execution. As a result, systems or applications relying on GnuTLS may be vulnerable to a denial of service or local privilege escalation attacks. (CVE-2025-9820)

- A flaw in GnuTLS DTLS handshake parsing allows malformed fragments with zero length and non-zero offset, leading to an integer underflow during reassembly and resulting in an out-of-bounds read. This issue is remotely exploitable and may cause information disclosure or denial of service. (CVE-2026-33845)

- A heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in merge_handshake_packet() where incoming handshake fragments are matched and merged based solely on handshake type, without validating that the message_length field remains consistent across all fragments of the same logical message. An attacker can exploit this by sending crafted DTLS fragments with conflicting message_length values, causing the implementation to allocate a buffer based on a smaller initial fragment and subsequently write beyond its bounds using larger, inconsistent fragments. Because the merge operation does not enforce proper bounds checking against the allocated buffer size, this results in an out-of-bounds write on the heap. The vulnerability is remotely exploitable without authentication via the DTLS handshake path and can lead to application crashes or potential memory corruption. (CVE-2026-33846)

- A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted Online Certificate Status Protocol (OCSP) response during a TLS handshake. Due to a logic error in how gnutls processes multi-record OCSP responses, a client with OCSP verification enabled may incorrectly accept a revoked server certificate, potentially leading to a compromise of trust. (CVE-2026-3832)

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 CentOS 9 Stream gnutls package.

Plugin Details

Severity: Medium

ID: 312106

File Name: centos9_gnutls-3_8_10-4_109502.nasl

Version: 1.1

Type: Local

Agent: unix

Family: CentOS Local Security Checks

Published: 5/4/2026

Updated: 5/4/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

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-2026-3833

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

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

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

Vulnerability Information

CPE: p-cpe:/a:centos:centos:gnutls-utils, p-cpe:/a:centos:centos:gnutls-c%2b%2b, p-cpe:/a:centos:centos:gnutls-devel, p-cpe:/a:centos:centos:gnutls, p-cpe:/a:centos:centos:gnutls-dane, cpe:/a:centos:centos:9

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/CentOS/release, Host/CentOS/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 4/30/2026

Vulnerability Publication Date: 11/21/2025

Reference Information

CVE: CVE-2025-9820, CVE-2026-33845, CVE-2026-33846, CVE-2026-3832, CVE-2026-3833, CVE-2026-42009, CVE-2026-42010, CVE-2026-42011, CVE-2026-42012, CVE-2026-42013, CVE-2026-42014, CVE-2026-42015, CVE-2026-5260, CVE-2026-5419

IAVA: 2025-A-0879-S, 2026-A-0405

Detections

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