RHSA-2026:49712 - Security Advisory

Topic

An update for golang is now available for Red Hat Enterprise Linux 9.6 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

The golang packages provide the Go programming language compiler.

Security Fix(es):

• net/mail: golang: net/mail: Denial of Service via pathological email address parsing (CVE-2026-42499)
• cmd/go: golang: Go command (cmd/go): Integrity bypass due to checksum validation flaw via malicious module proxy (CVE-2026-42501)
• html/template: golang: Go html/template: Cross-Site Scripting via improper URL escaping in meta tag content (CVE-2026-39823)
• cmd/go: golang: Go 'go bug' command: Arbitrary file overwrite via symlink attack (CVE-2026-39819)
• net/http/internal/http2: golang: golang.org/x/net: Go HTTP/2: Denial of Service via malformed SETTINGS_MAX_FRAME_SIZE frame (CVE-2026-33814)
• net/mail: golang: Go net/mail: Denial of Service via crafted email inputs (CVE-2026-39820)
• net: golang: Go net package: Denial of Service via long CNAME response in LookupCNAME (CVE-2026-33811)
• net/http/httputil: golang: net/http/httputil: ReverseProxy forwards hidden query parameters, potentially bypassing security controls (CVE-2026-39825)
• cmd/go: golang: Go tool pack: Arbitrary file write via malicious archive extraction (CVE-2026-39817)
• html/template: golang: html/template: Cross-site scripting due to incorrect script tag escaping (CVE-2026-39826)
• golang.org/x/net/idna: golang: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing (CVE-2026-39821)
• net/textproto: golang: Golang net/textproto: Misleading error messages via input injection (CVE-2026-42507)
• crypto/x509: golang: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries (CVE-2026-27145)
• os: golang: Go os.Root: Symlink following vulnerability allows directory traversal (CVE-2026-39822)

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 9.6 x86_64
• Red Hat Enterprise Linux Server - AUS 9.6 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.6 s390x
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.6 ppc64le
• Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.6 aarch64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.6 ppc64le
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.6 x86_64
• Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.6 aarch64
• Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.6 s390x
• Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.6 x86_64
• Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.6 aarch64
• Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.6 ppc64le
• Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 9.6 s390x

Fixes

• BZ - 2467809 - CVE-2026-42499 net/mail: golang: net/mail: Denial of Service via pathological email address parsing
• BZ - 2467811 - CVE-2026-39823 html/template: golang: Go html/template: Cross-Site Scripting via improper URL escaping in meta tag content
• BZ - 2467813 - CVE-2026-39819 cmd/go: golang: Go 'go bug' command: Arbitrary file overwrite via symlink attack
• BZ - 2467815 - CVE-2026-33814 net/http/internal/http2: golang: golang.org/x/net: Go HTTP/2: Denial of Service via malformed SETTINGS_MAX_FRAME_SIZE frame
• BZ - 2467820 - CVE-2026-39820 net/mail: golang: Go net/mail: Denial of Service via crafted email inputs
• BZ - 2467822 - CVE-2026-33811 net: golang: Go net package: Denial of Service via long CNAME response in LookupCNAME
• BZ - 2467823 - CVE-2026-39825 net/http/httputil: golang: net/http/httputil: ReverseProxy forwards hidden query parameters, potentially bypassing security controls
• BZ - 2467825 - CVE-2026-39817 cmd/go: golang: Go tool pack: Arbitrary file write via malicious archive extraction
• BZ - 2467826 - CVE-2026-39826 html/template: golang: html/template: Cross-site scripting due to incorrect script tag escaping
• BZ - 2480756 - CVE-2026-39821 golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing
• BZ - 2484205 - CVE-2026-42507 net/textproto: golang: Golang net/textproto: Misleading error messages via input injection
• BZ - 2484207 - CVE-2026-27145 crypto/x509: golang: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries
• BZ - 2498152 - CVE-2026-39822 golang: Go os.Root: Symlink following vulnerability allows directory traversal

CVEs

• CVE-2026-27145
• CVE-2026-33811
• CVE-2026-33814
• CVE-2026-39817
• CVE-2026-39819
• CVE-2026-39820
• CVE-2026-39821
• CVE-2026-39822
• CVE-2026-39823
• CVE-2026-39825
• CVE-2026-39826
• CVE-2026-42499
• CVE-2026-42501
• CVE-2026-42507

References

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