RHSA-2026:65886HighCVSS 8.2

Red Hat Security Advisory: image-builder security update

Published
September 9, 2026
Last Modified
September 19, 2026

🔗 CVE IDs covered (13)

CVE-2026-32280 →CVE-2026-32281 →CVE-2026-33811 →CVE-2026-33818 →CVE-2026-39821 →CVE-2026-42499 →CVE-2026-56862 →CVE-2026-39820 →CVE-2026-42504 →CVE-2026-56853 →CVE-2026-56858 →CVE-2026-56859 →CVE-2026-56860 →

📋 Description

CVE-2026-32280 — crypto/x509: crypto/tls: golang: Go: Denial of Service vulnerability in certificate chain building CVE-2026-32281 — crypto/x509: golang: Go crypto/x509: Denial of Service via inefficient certificate chain validation CVE-2026-33811 — net: golang: Go net package: Denial of Service via long CNAME response in LookupCNAME CVE-2026-33818 — encoding/asn1: golang: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal CVE-2026-39820 — net/mail: golang: Go net/mail: Denial of Service via crafted email inputs CVE-2026-39821 — golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing CVE-2026-42499 — net/mail: golang: net/mail: Denial of Service via pathological email address parsing CVE-2026-42504 — mime: golang: Golang MIME: Denial of Service via maliciously-crafted MIME header CVE-2026-56853 — net/http: golang: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service CVE-2026-56858 — html/template: golang: Go html/template: Cross-Site Scripting via pathological input CVE-2026-56859 — encoding/xml: golang: Go: Denial of Service via XML decoding recursion depth issue CVE-2026-56860 — net/url: golang: golang net/url: Denial of Service from quadratic complexity in path resolution CVE-2026-56862 — crypto/tls: golang: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages

🎯 Affected products14

  • Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-0:52.1-1.el9_8.2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-0:52.1-1.el9_8.2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-0:52.1-1.el9_8.2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-0:52.1-1.el9_8.2.src as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-0:52.1-1.el9_8.2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-debuginfo-0:52.1-1.el9_8.2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-debuginfo-0:52.1-1.el9_8.2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-debuginfo-0:52.1-1.el9_8.2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-debuginfo-0:52.1-1.el9_8.2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-debugsource-0:52.1-1.el9_8.2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-debugsource-0:52.1-1.el9_8.2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-debugsource-0:52.1-1.el9_8.2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • image-builder-debugsource-0:52.1-1.el9_8.2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)

✅ Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Workaround: To mitigate this issue, applications can be configured to use the pure Go DNS resolver instead of the `cgo` DNS resolver. This can be achieved by setting the `GODEBUG` environment variable to `netdns=go`. For example, to run a Go application with this mitigation: `GODEBUG=netdns=go /path/to/your/go/application`. This change may require restarting affected applications or services to take effect. Users should verify that this change does not negatively impact DNS resolution for their specific application environment. Workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Workaround: Upgrade to a fixed golang.org/x/net release that includes the idna correction, via updated golang or dependent package rebuilds. Workaround: To mitigate this issue, restrict network access to services that process MIME headers from untrusted sources. Implement input validation and sanitization for all incoming data, especially MIME headers, to prevent maliciously crafted content from being processed by applications utilizing the vulnerable Golang MIME package.

🔗 References (16)