RHSA-2026:55899HighCVSS 7.5

Red Hat Security Advisory: Red Hat Web Terminal Operator 1.16.1 release.

Published
August 18, 2026
Last Modified
August 23, 2026

🔗 CVE IDs covered (2)

CVE-2026-27145 →CVE-2026-39836 →

📋 Description

CVE-2026-27145 — crypto/x509: golang: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries CVE-2026-39836 — net: golang: Go net package: Denial of Service via NUL byte in Dial and LookupPort on Windows

🎯 Affected products5

  • Red Hat Web Terminal 1.16
  • registry.redhat.io/web-terminal/web-terminal-exec-rhel9@sha256:7ffa72ca4032f0435dd79b3bcc72f5bed957506558244340c23daee76543d272_amd64 as a component of Red Hat Web Terminal 1.16
  • registry.redhat.io/web-terminal/web-terminal-operator-bundle@sha256:87a742f7146eea015d6f078c3da94453043e5dc71ebe649618f600fe57ddf68d_amd64 as a component of Red Hat Web Terminal 1.16
  • registry.redhat.io/web-terminal/web-terminal-rhel9-operator@sha256:0880560f5d2aa6a707d55d3b2c27f0eaee1dcf985e9fda7fc51be92ed79364ef_amd64 as a component of Red Hat Web Terminal 1.16
  • registry.redhat.io/web-terminal/web-terminal-tooling-rhel9@sha256:3332a2966bcdda130d6938366e51b685294604842bcd973cf46e8e7770509124_amd64 as a component of Red Hat Web Terminal 1.16

✅ Remediation

To start using the Web Terminal Operator, install the Web Terminal Operator from OpenShift OperatorHub on OpenShift Container Platform 4.21 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.

🔗 References (7)