RHSA-2026:12033 - Security Advisory

Topic

An update for gvisor-tap-vsock is now available for Red Hat Enterprise Linux 9.4 Extended Update Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

A replacement for libslirp and VPNKit, written in pure Go. It is based on the network stack of gVisor and is used to provide networking for podman-machine virtual machines. 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.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 9.4 x86_64
• Red Hat Enterprise Linux Server - AUS 9.4 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.4 s390x
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.4 ppc64le
• Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.4 aarch64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.4 ppc64le
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.4 x86_64
• Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.4 aarch64
• Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.4 s390x
• Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.4 x86_64
• Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.4 aarch64
• Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.4 ppc64le
• Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 9.4 s390x

Fixes

• BZ - 2418462 - CVE-2025-61729 crypto/x509: golang: Denial of Service due to excessive resource consumption via crafted certificate
• BZ - 2434432 - CVE-2025-61726 golang: net/url: Memory exhaustion in query parameter parsing in net/url
• BZ - 2437111 - CVE-2025-68121 crypto/tls: crypto/tls: Incorrect certificate validation during TLS session resumption
• BZ - 2445356 - CVE-2026-25679 net/url: Incorrect parsing of IPv6 host literals in net/url

CVEs

• CVE-2025-61726
• CVE-2025-61729
• CVE-2025-68121
• CVE-2026-25679

References

• https://access.redhat.com/security/updates/classification/#important