RHSA-2026:69235 - Security Advisory

Topic

An update for osbuild-composer is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On.

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 service for building customized OS artifacts, such as VM images and OSTree commits, that uses osbuild under the hood. Besides building images for local usage, it can also upload images directly to cloud. It is compatible with composer-cli and cockpit-composer clients.

Security Fix(es):

• golang-fips: Golang FIPS zeroed buffer (CVE-2024-9355)
• golang: net/http: net/http: sensitive headers incorrectly sent after cross-domain redirect (CVE-2024-45336)
• crypto/internal/nistec: golang: Timing sidechannel for P-256 on ppc64le in crypto/internal/nistec (CVE-2025-22866)
• crypto/tls: crypto/tls: Incorrect certificate validation during TLS session resumption (CVE-2025-68121)
• crypto/x509: golang: Go crypto/x509: Denial of Service via inefficient certificate chain validation (CVE-2026-32281)
• crypto/x509: golang: Go crypto/x509: Certificate validation bypass due to incorrect DNS constraint application (CVE-2026-33810)
• golang: internal/syscall/unix: Root.Chmod can follow symlinks out of the root (CVE-2026-32282)
• crypto/tls: golang: Go crypto/tls: Denial of Service via multiple TLS 1.3 key update messages (CVE-2026-32283)
• crypto/x509: crypto/tls: golang: Go: Denial of Service vulnerability in certificate chain building (CVE-2026-32280)
• golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing (CVE-2026-39821)
• mime: golang: Golang MIME: Denial of Service via maliciously-crafted MIME header (CVE-2026-42504)
• encoding/asn1: golang: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal (CVE-2026-33818)
• net/url: golang: golang net/url: Denial of Service from quadratic complexity in path resolution (CVE-2026-56860)
• net/http: golang: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service (CVE-2026-56853)
• html/template: golang: Go html/template: Cross-Site Scripting via pathological input (CVE-2026-56858)
• crypto/tls: golang: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages (CVE-2026-56862)
• encoding/xml: golang: Go: Denial of Service via XML decoding recursion depth issue (CVE-2026-56859)

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 Life Cycle Long Life 8.6 x86_64
• Red Hat Enterprise Linux Server - AUS 8.6 x86_64
• Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle Long Life 8.6 aarch64
• Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle Long Life 8.6 ppc64le
• Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle Long Life 8.6 s390x

Fixes

• BZ - 2315719 - CVE-2024-9355 golang-fips: Golang FIPS zeroed buffer
• BZ - 2341751 - CVE-2024-45336 golang: net/http: net/http: sensitive headers incorrectly sent after cross-domain redirect
• BZ - 2344219 - CVE-2025-22866 crypto/internal/nistec: golang: Timing sidechannel for P-256 on ppc64le in crypto/internal/nistec
• BZ - 2437111 - CVE-2025-68121 crypto/tls: crypto/tls: Incorrect certificate validation during TLS session resumption
• BZ - 2456333 - CVE-2026-32281 crypto/x509: golang: Go crypto/x509: Denial of Service via inefficient certificate chain validation
• BZ - 2456335 - CVE-2026-33810 crypto/x509: golang: Go crypto/x509: Certificate validation bypass due to incorrect DNS constraint application
• BZ - 2456336 - CVE-2026-32282 golang: internal/syscall/unix: Root.Chmod can follow symlinks out of the root
• BZ - 2456338 - CVE-2026-32283 crypto/tls: golang: Go crypto/tls: Denial of Service via multiple TLS 1.3 key update messages
• BZ - 2456339 - CVE-2026-32280 crypto/x509: crypto/tls: golang: Go: Denial of Service vulnerability in certificate chain building
• 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 - 2484204 - CVE-2026-42504 mime: golang: Golang MIME: Denial of Service via maliciously-crafted MIME header
• BZ - 2515815 - CVE-2026-33818 encoding/asn1: golang: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal
• BZ - 2515820 - CVE-2026-56860 net/url: golang: golang net/url: Denial of Service from quadratic complexity in path resolution
• BZ - 2515827 - CVE-2026-56853 net/http: golang: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service
• BZ - 2515838 - CVE-2026-56858 html/template: golang: Go html/template: Cross-Site Scripting via pathological input
• BZ - 2515839 - CVE-2026-56862 crypto/tls: golang: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages
• BZ - 2515840 - CVE-2026-56859 encoding/xml: golang: Go: Denial of Service via XML decoding recursion depth issue

CVEs

• CVE-2024-9355
• CVE-2024-45336
• CVE-2025-22866
• CVE-2025-68121
• CVE-2026-32280
• CVE-2026-32281
• CVE-2026-32282
• CVE-2026-32283
• CVE-2026-33810
• CVE-2026-33818
• CVE-2026-39821
• CVE-2026-42504
• CVE-2026-56853
• CVE-2026-56858
• CVE-2026-56859
• CVE-2026-56860
• CVE-2026-56862

References

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