RHSA-2026:87246HighCVSS 8.8

Red Hat Security Advisory: go-toolset:rhel8 security, bug fix, and enhancement update

Published
October 21, 2026
Last Modified
October 21, 2026

🔗 CVE IDs covered (27)

CVE-2025-22866 →CVE-2025-68121 →CVE-2026-27143 →CVE-2026-32283 →CVE-2026-56860 →CVE-2026-111943 →CVE-2024-45336 →CVE-2026-27137 →CVE-2026-27145 →CVE-2026-33814 →CVE-2026-39821 →CVE-2026-42504 →CVE-2026-56859 →CVE-2025-22874 →CVE-2026-32280 →CVE-2026-32281 →CVE-2026-32282 →CVE-2026-33810 →CVE-2026-33811 →CVE-2026-33818 →CVE-2026-39820 →CVE-2025-4673 →CVE-2026-27144 →CVE-2026-42499 →CVE-2026-56853 →CVE-2026-56858 →CVE-2026-56862 →

📋 Description

CVE-2024-45336 — golang: net/http: net/http: sensitive headers incorrectly sent after cross-domain redirect CVE-2025-4673 — net/http: Sensitive headers not cleared on cross-origin redirect in net/http CVE-2025-22866 — crypto/internal/nistec: golang: Timing sidechannel for P-256 on ppc64le in crypto/internal/nistec CVE-2025-22874 — crypto/x509: Usage of ExtKeyUsageAny disables policy validation in crypto/x509 CVE-2025-68121 — crypto/tls: crypto/tls: Incorrect certificate validation during TLS session resumption CVE-2026-27137 — crypto/x509: Incorrect enforcement of email constraints in crypto/x509 CVE-2026-27143 — golang: cmd/compile: possible memory corruption after bound check elimination CVE-2026-27144 — golang: cmd/compile: no-op interface conversion bypasses overlap checking 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-2026-32283 — crypto/tls: golang: Go crypto/tls: Denial of Service via multiple TLS 1.3 key update messages 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-2026-33814 — net/http/internal/http2: golang: golang.org/x/net: Go HTTP/2: Denial of Service via malformed SETTINGS_MAX_FRAME_SIZE frame CVE-2026-33818 — 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 CVE-2026-111943 — crypto/x509: golang: crypto/x509: Man-in-the-middle attacks via untrusted intermediate certificates

🎯 Affected products28

  • Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • delve-0:1.26.1-1.module+el8.6.0+24782+a062e766.src (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • delve-0:1.26.1-1.module+el8.6.0+24782+a062e766.src (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • delve-0:1.26.1-1.module+el8.6.0+24782+a062e766.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • delve-0:1.26.1-1.module+el8.6.0+24782+a062e766.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • delve-debuginfo-0:1.26.1-1.module+el8.6.0+24782+a062e766.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • delve-debuginfo-0:1.26.1-1.module+el8.6.0+24782+a062e766.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • delve-debugsource-0:1.26.1-1.module+el8.6.0+24782+a062e766.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • delve-debugsource-0:1.26.1-1.module+el8.6.0+24782+a062e766.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • go-toolset-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • go-toolset-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • golang-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.src (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • golang-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.src (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • golang-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • golang-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • golang-bin-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • golang-bin-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • golang-docs-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.noarch (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • golang-docs-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.noarch (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • golang-misc-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.noarch (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • golang-misc-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.noarch (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • golang-race-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • golang-race-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.x86_64 (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • golang-src-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.noarch (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • golang-src-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.noarch (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)
  • golang-tests-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.noarch (go-toolset:rhel8) as a component of Red Hat Enterprise Linux AppStream AUS (v.8.6)
  • golang-tests-0:1.26.10-4.module+el8.6.0+25114+90ecdb41.noarch (go-toolset:rhel8) 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: To mitigate this vulnerability, strictly sanitize and enforce bounds checking on any untrusted user input that influences loop counters, iteration limits, or memory indices. If there is no integer overflow or underflow, the out-of-bounds access cannot occur. Workaround: To mitigate this issue, review code that performs memory copies or struct assignments. If data is being passed through an interface (such as 'any' or 'interface{}') just before a move operation, refactor the code to use concrete types or explicit pointers instead. 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: See the security bulletin for a detailed mitigation procedure.

🔗 References (33)