RHSA-2026:22121HighCVSS 7.5

Red Hat Security Advisory: golang security update

Published
June 1, 2026
Last Modified
August 26, 2026

🔗 CVE IDs covered (11)

CVE-2026-33814 →CVE-2026-39819 →CVE-2026-39823 →CVE-2026-39825 →CVE-2026-39826 →CVE-2026-42499 →CVE-2026-39817 →CVE-2026-39820 →CVE-2026-39836 →CVE-2026-42501 →CVE-2026-33811 →

📋 Description

CVE-2026-33811 — net: golang: Go net package: Denial of Service via long CNAME response in LookupCNAME CVE-2026-33814 — net/http/internal/http2: golang: golang.org/x/net: Go HTTP/2: Denial of Service via malformed SETTINGS_MAX_FRAME_SIZE frame CVE-2026-39817 — cmd/go: golang: Go tool pack: Arbitrary file write via malicious archive extraction CVE-2026-39819 — cmd/go: golang: Go 'go bug' command: Arbitrary file overwrite via symlink attack CVE-2026-39820 — net/mail: golang: Go net/mail: Denial of Service via crafted email inputs CVE-2026-39823 — html/template: golang: Go html/template: Cross-Site Scripting via improper URL escaping in meta tag content CVE-2026-39825 — net/http/httputil: golang: net/http/httputil: ReverseProxy forwards hidden query parameters, potentially bypassing security controls CVE-2026-39826 — html/template: golang: html/template: Cross-site scripting due to incorrect script tag escaping CVE-2026-39836 — net: golang: Go net package: Denial of Service via NUL byte in Dial and LookupPort on Windows CVE-2026-42499 — net/mail: golang: net/mail: Denial of Service via pathological email address parsing CVE-2026-42501 — cmd/go: golang: Go command (cmd/go): Integrity bypass due to checksum validation flaw via malicious module proxy

🎯 Affected products22

  • Red Hat Enterprise Linux AppStream (v. 9)
  • go-toolset-0:1.26.3-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • go-toolset-0:1.26.3-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • go-toolset-0:1.26.3-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • go-toolset-0:1.26.3-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-0:1.26.3-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-0:1.26.3-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-0:1.26.3-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-0:1.26.3-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-0:1.26.3-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-bin-0:1.26.3-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-bin-0:1.26.3-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-bin-0:1.26.3-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-bin-0:1.26.3-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-docs-0:1.26.3-1.el9_8.noarch as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-misc-0:1.26.3-1.el9_8.noarch as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-race-0:1.26.3-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-race-0:1.26.3-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-race-0:1.26.3-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-race-0:1.26.3-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-src-0:1.26.3-1.el9_8.noarch as a component of Red Hat Enterprise Linux AppStream (v. 9)
  • golang-tests-0:1.26.3-1.el9_8.noarch 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: 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: Ensure that user-supplied URLs are validated and sanitized before being passed to Go's `html/template` package for rendering in HTML meta tag content attributes. Avoid rendering untrusted URL data directly in meta tag content attributes. Workaround: Increase the maximum number of query parameters allowed by setting the GODEBUG environment variable `urlmaxqueryparams` to a higher value (e.g., `GODEBUG=urlmaxqueryparams=20000`), or validate and enforce security controls on query parameters at the backend service rather than relying solely on the ReverseProxy's Rewrite or Director function for security filtering. Workaround: To verify the integrity of Go module dependencies and detect potential tampering by a malicious proxy, users can revalidate all dependencies of the current module. This process involves removing the existing `go.sum` file and then re-generating and verifying module checksums. Execute the following commands in your module's root directory: ```bash rm go.sum go mod tidy go mod verify ``` This operation will re-download and re-verify all module dependencies. Be aware that this may affect your local module cache and could require re-building projects.

🔗 References (15)