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Public proof of conceptFix availableAwaiting NVD analysis

CVE-2026-111943

Distrust compromised intermediate certificates in crypto/x509

A public proof of concept exists; no exploitation attested.

  • Published2026-10-21
  • Fixed in1.27.3 · 1.26.10
  • WeaknessCWE-299

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

On most platforms, Go uses the given system root certificates. However, in some narrower cases, the system trust stores may not be updated without further action. To defend against the narrower set of cases that may remain affected, a denylist was added in crypto/x509 to return an error when calling Verify with any of the known intermediate certificates that are no longer considered to be trustworthy.

Timeline

dates in UTC
  1. 2026-10-2101:17CVE publishedNVD
  2. 2026-10-2318:46First public proof of conceptPoC-in-GitHub

Versions per branch

OSV
golang
BranchAffectedFixed in
1.27≥ 1.27.0-0, < 1.27.31.27.3
1.26< 1.26.101.26.10
rustls-webpki
BranchAffectedFixed in
0.104≥ 0.104.0-alpha.1, < 0.104.0-alpha.80.104.0-alpha.8
0.x≥ 0.0.0-0, < 0.103.160.103.16
stdlib
BranchAffectedFixed in
1.27≥ 1.27.0-0, < 1.27.31.27.3
1.26< 1.26.101.26.10

2 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As Go, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Go standard library crypto/x509other versions: not affected

    package crypto/x509https://pkg.go.dev

    Affected
    • < 1.26.10fixed in 1.26.10semver
    • ≥ 1.27.0-0, < 1.27.3fixed in 1.27.3semver

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-10-21

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • aardvark-dnsRocky Linux:8all versions · fixed in 2:1.10.1-2.module+el8.10.0+1874+ce489889
  • aardvark-dnsRocky Linux:8all versions · fixed in 2:1.10.1-2.module+el8.10.0+1880+8e896d1b
  • aardvark-dnsRocky Linux:8all versions · fixed in 2:1.10.1-2.module+el8.10.0+1896+b18fa106
  • aardvark-dnsRocky Linux:8all versions · fixed in 2:1.10.1-2.module+el8.10.0+1948+4b5cd4a9
  • aardvark-dnsRocky Linux:8all versions · fixed in 2:1.10.1-2.module+el8.10.0+2001+6a33db9f
  • aardvark-dnsRocky Linux:8all versions · fixed in 2:1.10.1-2.module+el8.10.0+40047+0c0a73f4
  • aardvark-dnsRocky Linux:8all versions · fixed in 2:1.10.1-2.module+el8.10.0+40133+32c21f88
  • aardvark-dnsAlmaLinux:8all versions · fixed in 2:1.10.1-2.module_el8.10.0+3901+4b80ecd7

524 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-111943 Red Hat Product Security7,903 products fixed · 265 known affected

    crypto/x509: golang: crypto/x509: Man-in-the-middle attacks via untrusted intermediate certificates

    ansible-automation-platform/automation-orchestrator-operator-bundle as a component of Ansible Automation Orchestrator 2026 · ansible-automation-platform/automation-orchestrator-rhel9-operator as a component of Ansible Automation Orchestrator 2026 · ansible-automation-platform/automation-orchestrator-temporal-rhel9 as a component of Ansible Automation Orchestrator 2026 · +262 more

  • RHSA-2026:95209 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Updated Red Hat OpenStack Platform 17.1 director Operator container images

  • RHSA-2026:95206 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Updated Red Hat OpenStack Platform 16.2 director Operator container images

  • RHSA-2026:95014 Red Hat Product Security5 products fixed

    Red Hat Security Advisory: opentelemetry-collector security update

  • RHSA-2026:95015 Red Hat Product Security5 products fixed

    Red Hat Security Advisory: opentelemetry-collector security update

  • RHSA-2026:95016 Red Hat Product Security5 products fixed

    Red Hat Security Advisory: opentelemetry-collector security update

173 more advisories

Full record on NVD

Fix

  1. Update golang to 1.27.3 · 1.26.10
  2. Vendor fix Red Hat Product Security RHSA-2026:95209 · 2 productsThe container images provided by this update can be downloaded from the Red Hat container registry at registry.redhat.io or registry.access.redhat.com using the 'podman pull' command. For more information about the images, search the image name in the Red Hat Ecosystem Catalog.
  3. Vendor fix Red Hat Product Security RHSA-2026:95014 · 5 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2026:92286 · 26 productsFor OpenShift Container Platform 4.21 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
  5. Vendor fix Red Hat Product Security RHSA-2026:94575 · 4 productsBefore installing the operator, make sure all previously released errata relevant to your system have been applied. The steps to apply the upgraded images will differ depending on the installation plan approval policy that will be used while installing the zero trust workload identity manager for …
  6. Vendor fix Red Hat Product Security RHSA-2026:94562 · 1 productFor Windows Machine Config Operator upgrades, see the following documentation: https://docs.redhat.com/en/documentation/openshift_container_platform/5.0/html-single/windows_container_support_for_openshift/index#windows-node-upgrades
  7. Vendor fix Red Hat Product Security RHSA-2026:92859 · 2 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258

Detection

read 2026-11-05 19:20 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Published
2026-10-21
Last Modified
2026-10-30
NVD status
Awaiting Analysis

Frequently asked questions

What is CVE-2026-111943?

On most platforms, Go uses the given system root certificates. However, in some narrower cases, the system trust stores may not be updated without further action. To defend against the narrower set of cases that may remain affected, a denylist was added in crypto/x509 to return an error when calling Verify with any of the known intermediate certificates that are no longer considered to be trustworthy.

Is CVE-2026-111943 actively exploited?

Active exploitation of CVE-2026-111943 has not been confirmed. Its EPSS score was 0.4% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-111943?

CVE-2026-111943 has a CVSS v3 base score of 6.8 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N.

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