RHEL 9 : gvisor-tap-vsock (RHSA-2026:9108)

critical Nessus Plugin ID 307643

Synopsis

The remote Red Hat host is missing one or more security updates for gvisor-tap-vsock.

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:9108 advisory.

A replacement for libslirp and VPNKit, written in pure Go. It is based on the network stack of gVisor.
Compared to libslirp, gvisor-tap-vsock brings a configurable DNS server and dynamic port forwarding.

Security Fix(es):

* crypto/x509: golang: Denial of Service due to excessive resource consumption via crafted certificate (CVE-2025-61729)

* golang: net/url: Memory exhaustion in query parameter parsing in net/url (CVE-2025-61726)

* crypto/tls: Unexpected session resumption in crypto/tls (CVE-2025-68121)

* net/url: Incorrect parsing of IPv6 host literals in net/url (CVE-2026-25679)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise 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 RHEL gvisor-tap-vsock package based on the guidance in RHSA-2026:9108.

Plugin Details

Severity: Critical

ID: 307643

File Name: redhat-RHSA-2026-9108.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 4/20/2026

Updated: 4/20/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 8.1

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

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

CVSS Score Source: CVE-2025-68121

CVSS v3

Risk Factor: Critical

Base Score: 10

Temporal Score: 9

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

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

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:gvisor-tap-vsock-gvforwarder, p-cpe:/a:redhat:enterprise_linux:gvisor-tap-vsock, cpe:/o:redhat:rhel_eus:9.6

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/20/2026

Vulnerability Publication Date: 12/2/2025

Reference Information

CVE: CVE-2025-61726, CVE-2025-61729, CVE-2025-68121, CVE-2026-25679

CWE: 1050, 1286, 770

RHSA: 2026:9108

Detections

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