RHSA-2026:90725HighCVSS 8.2

Red Hat Security Advisory: rhc security update

Published
October 27, 2026
Last Modified
November 2, 2026

🔗 CVE IDs covered (18)

CVE-2026-27145 →CVE-2026-78669 →CVE-2024-9355 →CVE-2025-68121 →CVE-2026-56858 →CVE-2026-56860 →CVE-2026-111943 →CVE-2026-32280 →CVE-2026-32282 →CVE-2026-32283 →CVE-2026-33811 →CVE-2026-33818 →CVE-2026-39821 →CVE-2026-42504 →CVE-2024-45336 →CVE-2026-56862 →CVE-2026-78667 →CVE-2026-97031 →

📋 Description

CVE-2024-9355 — golang-fips: Golang FIPS zeroed buffer CVE-2024-45336 — golang: net/http: net/http: sensitive headers incorrectly sent after cross-domain redirect CVE-2025-68121 — crypto/tls: crypto/tls: Incorrect certificate validation during TLS session resumption CVE-2026-27145 — crypto/x509: golang: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries CVE-2026-32280 — crypto/x509: crypto/tls: golang: Go: Denial of Service vulnerability in certificate chain building CVE-2026-32282 — golang: internal/syscall/unix: Root.Chmod can follow symlinks out of the root CVE-2026-32283 — crypto/tls: golang: Go crypto/tls: Denial of Service via multiple TLS 1.3 key update messages 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-2026-39821 — golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing CVE-2026-42504 — mime: golang: Golang MIME: Denial of Service via maliciously-crafted MIME header CVE-2026-56858 — html/template: golang: Go html/template: Cross-Site Scripting via pathological input 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 CVE-2026-78667 — net/http: golang: golang: Denial of Service via crafted HTTP Range headers CVE-2026-78669 — net/http: net/http/internal/http2: golang.org/x/net/http2: net/http: Denial of Service via excessive HTTP/2 SETTINGS frames CVE-2026-97031 — crypto/tls: golang: crypto/tls: Denial of Service via multiple ECH outer extension references CVE-2026-111943 — crypto/x509: golang: crypto/x509: Man-in-the-middle attacks via untrusted intermediate certificates

🎯 Affected products10

  • Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • rhc-1:0.2.1-14.el8_6.1.src as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • rhc-1:0.2.1-14.el8_6.1.src as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • rhc-1:0.2.1-14.el8_6.1.x86_64 as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • rhc-1:0.2.1-14.el8_6.1.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • rhc-debuginfo-1:0.2.1-14.el8_6.1.x86_64 as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • rhc-debuginfo-1:0.2.1-14.el8_6.1.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • rhc-debugsource-1:0.2.1-14.el8_6.1.x86_64 as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • rhc-debugsource-1:0.2.1-14.el8_6.1.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)

✅ 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: 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: A flaw was found in the Go standard library crypto/x509 package. When verifying a TLS certificate hostname, VerifyHostname processed each DNS Subject Alternative Name (SAN) entry in a loop and repeatedly split the candidate hostname on "." characters. For certificates with a very large DNS SAN list, CPU use could grow quadratically with the number of SAN entries and hostname labels. Because hostname verification runs before the certificate chain is built, this overhead can occur even when the certificate is not trusted. Red Hat rates this issue as Important. It affects Red Hat products that include the Go standard library crypto/x509 code from an affected Go toolchain version (before Go 1.25.11, or from Go 1.26.0 through Go 1.26.3). Applications and container images built with a fixed Go release (1.25.11 or later, or 1.26.4 or later) are not affected. Community distributions such as Fedora are also affected. Upstream fix: Go 1.25.11 and Go 1.26.4 (GO-2026-5037). 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: 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. Workaround: In case you consume HTTP2, upgrade to a patched version of the http module. Verify: ``` go version go list -m golang.org/x/net govulncheck ./... ``` Workaround: See the security bulletin for a detailed mitigation procedure.

🔗 References (21)