RHSA-2026:76809HighCVSS 8.8

Red Hat Security Advisory: grafana security update

Published
October 6, 2026
Last Modified
October 6, 2026

🔗 CVE IDs covered (14)

CVE-2026-42504 →CVE-2026-56853 →CVE-2026-56858 →CVE-2026-33376 →CVE-2026-39821 →CVE-2026-42499 →CVE-2026-56859 →CVE-2026-56860 →CVE-2026-56862 →CVE-2026-27137 →CVE-2026-33377 →CVE-2026-33810 →CVE-2026-33818 →CVE-2026-39820 →

📋 Description

CVE-2026-27137 — crypto/x509: Incorrect enforcement of email constraints in crypto/x509 CVE-2026-33376 — grafana: Grafana Auth Proxy: Unauthorized access due to incorrect IPv6 allow-list default CVE-2026-33377 — grafana: Grafana: Privilege escalation via dashboard overwrite CVE-2026-33810 — crypto/x509: golang: Go crypto/x509: Certificate validation bypass due to incorrect DNS constraint application 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 E4S (v.9.2)
  • grafana-0:9.0.9-13.el9_2.aarch64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-0:9.0.9-13.el9_2.ppc64le as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-0:9.0.9-13.el9_2.s390x as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-0:9.0.9-13.el9_2.src as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-0:9.0.9-13.el9_2.x86_64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-debuginfo-0:9.0.9-13.el9_2.aarch64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-debuginfo-0:9.0.9-13.el9_2.ppc64le as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-debuginfo-0:9.0.9-13.el9_2.s390x as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-debuginfo-0:9.0.9-13.el9_2.x86_64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-debugsource-0:9.0.9-13.el9_2.aarch64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-debugsource-0:9.0.9-13.el9_2.ppc64le as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-debugsource-0:9.0.9-13.el9_2.s390x as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)
  • grafana-debugsource-0:9.0.9-13.el9_2.x86_64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.2)

✅ 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, explicitly specify the intended IPv6 address mask—typically /128 for a single host—within the Grafana Auth Proxy allow-list configuration. This overrides the incorrect default /32 mask, ensuring that network access restrictions are applied strictly as intended. For RHEL: Update the whitelist directive under the [auth.proxy] section in /etc/grafana/grafana.ini. For example, if ::1 is the desired address, configure it explicitly as ::1/128. A restart of the Grafana service (systemctl restart grafana-server) is required for the changes to take effect. Workaround: Audit dashboard-level permissions to ensure that write access is granted only to users who should be able to modify each specific dashboard. Revoke per-dashboard write permissions from Editor users who do not strictly require them. 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 (17)