RHSA-2026:98502 - Security Advisory

Topic

An update for gvisor-tap-vsock is now available for Red Hat Enterprise Linux 9.

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. Compared to libslirp, gvisor-tap-vsock brings a configurable DNS server and dynamic port forwarding.

Security Fix(es):

• encoding/asn1: golang: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal (CVE-2026-33818)
• net/http: golang: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service (CVE-2026-56853)
• crypto/tls: golang: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages (CVE-2026-56862)
• net/http: golang: golang: Denial of Service via crafted HTTP Range headers (CVE-2026-78667)
• crypto/tls: golang: crypto/tls: Denial of Service via multiple ECH outer extension references (CVE-2026-97031)
• net/textproto: mime/multipart: golang: golang: Denial of Service via memory limit bypass in multipart form parsing (CVE-2026-94440)
• crypto/x509: golang: crypto/x509: Man-in-the-middle attacks via untrusted intermediate certificates (CVE-2026-111943)

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 9 x86_64
• Red Hat Enterprise Linux for IBM z Systems 9 s390x
• Red Hat Enterprise Linux for Power, little endian 9 ppc64le
• Red Hat Enterprise Linux for ARM 64 9 aarch64

Fixes

• BZ - 2515815 - CVE-2026-33818 encoding/asn1: golang: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal
• BZ - 2515827 - CVE-2026-56853 net/http: golang: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service
• BZ - 2515839 - CVE-2026-56862 crypto/tls: golang: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages
• BZ - 2548334 - CVE-2026-78667 net/http: golang: golang: Denial of Service via crafted HTTP Range headers
• BZ - 2548336 - CVE-2026-97031 crypto/tls: golang: crypto/tls: Denial of Service via multiple ECH outer extension references
• BZ - 2548341 - CVE-2026-94440 net/textproto: mime/multipart: golang: golang: Denial of Service via memory limit bypass in multipart form parsing
• BZ - 2556068 - CVE-2026-111943 crypto/x509: golang: crypto/x509: Man-in-the-middle attacks via untrusted intermediate certificates

CVEs

• CVE-2026-33818
• CVE-2026-56853
• CVE-2026-56862
• CVE-2026-78667
• CVE-2026-94440
• CVE-2026-97031
• CVE-2026-111943

References

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