RHSA-2026:42050HighCVSS 8.8

Red Hat Security Advisory: Red Hat Web Terminal Operator 1.13.0 release.

Published
July 20, 2026
Last Modified
September 15, 2026

🔗 CVE IDs covered (8)

CVE-2026-33811 →CVE-2026-39821 →CVE-2026-42504 →CVE-2026-27145 →CVE-2026-32280 →CVE-2026-32281 →CVE-2026-32282 →CVE-2026-33810 →

📋 Description

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-2026-32281 — crypto/x509: golang: Go crypto/x509: Denial of Service via inefficient certificate chain validation CVE-2026-32282 — golang: internal/syscall/unix: Root.Chmod can follow symlinks out of the root CVE-2026-33810 — crypto/x509: golang: Go crypto/x509: Certificate validation bypass due to incorrect DNS constraint application CVE-2026-33811 — net: golang: Go net package: Denial of Service via long CNAME response in LookupCNAME 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

🎯 Affected products5

  • Red Hat Web Terminal 1.13
  • registry.redhat.io/web-terminal/web-terminal-exec-rhel9@sha256:a6cb6402795d9d9ea0e1b68edcaf59ee008b18b00f91a54aa6686993d47a2a77_amd64 as a component of Red Hat Web Terminal 1.13
  • registry.redhat.io/web-terminal/web-terminal-operator-bundle@sha256:4b8a34706b2dd9aa95ce68a9bf4813946d311bf7626923a843472b05cfbc8492_amd64 as a component of Red Hat Web Terminal 1.13
  • registry.redhat.io/web-terminal/web-terminal-rhel9-operator@sha256:6791ddb17bc6910099b3277295b24229cec10c0da7b5599d753357673f08c1cd_amd64 as a component of Red Hat Web Terminal 1.13
  • registry.redhat.io/web-terminal/web-terminal-tooling-rhel9@sha256:78241066bb3746b9501e5cfd0ce5b6322b1f908309b5e0b145eac28c73d20662_amd64 as a component of Red Hat Web Terminal 1.13

✅ Remediation

To start using the Web Terminal Operator, install the Web Terminal Operator from OpenShift OperatorHub on OpenShift Container Platform 4.18 or higher. 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: 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: 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 (19)