Github.com/cloudflare/circl: circl-fourq: missing and wrong validation can lead to incorrect results

Description

A flaw was found in CIRCL's implementation of the FourQ elliptic curve. This vulnerability allows an attacker to compromise session security via low-order point injection and incorrect point validation during Diffie-Hellman key exchange.

Scores

EPSS (exploitation in 30 days)

0.53% · top 55% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.7.

Weakness

• CWE-1287: Improper Validation of Specified Type of Input (opens in a new tab)All about CWE-1287 and its CVEs

Affected products

• circl

  • affected < 1.6.1

• Red Hat · Builds for Red Hat OpenShift

  All versions: affected

• Red Hat · Builds for Red Hat OpenShift

  All versions: affected

• Red Hat · Builds for Red Hat OpenShift

  All versions: affected

• Red Hat · Builds for Red Hat OpenShift

  All versions: affected

• Red Hat · Builds for Red Hat OpenShift

  All versions: affected

• Red Hat · Builds for Red Hat OpenShift

  All versions: affected

• Red Hat · Custom Metric Autoscaler operator for Red Hat Openshift

  All versions: affected

• Red Hat · Custom Metric Autoscaler operator for Red Hat Openshift

  All versions: affected

• Red Hat · Custom Metric Autoscaler operator for Red Hat Openshift

  All versions: affected

• Red Hat · Custom Metric Autoscaler operator for Red Hat Openshift

  All versions: affected

• Red Hat · Custom Metric Autoscaler operator for Red Hat Openshift

  All versions: affected

• Red Hat · Multicluster Global Hub

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Pipelines

  All versions: affected

• Red Hat · OpenShift Serverless

  All versions: affected

• Red Hat · OpenShift Serverless

  All versions: affected

• Red Hat · OpenShift Serverless

  All versions: affected

• Red Hat · OpenShift Serverless

  All versions: affected

• Red Hat · OpenShift Service Mesh 3

  All versions: affected

• Red Hat · OpenShift Service Mesh 3

  All versions: affected

• Red Hat · OpenShift Service Mesh 3

  All versions: affected

• Red Hat · OpenShift Service Mesh 3

  All versions: affected

• Red Hat · OpenShift Service Mesh 3

  All versions: affected

• Red Hat · OpenShift Service Mesh 3

  All versions: affected

• Red Hat · OpenShift Service Mesh 3

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Advanced Cluster Security 4

  All versions: affected

• Red Hat · Red Hat Ceph Storage 5

  All versions: affected

• Red Hat · Red Hat Ceph Storage 5

  All versions: affected

• Red Hat · Red Hat Ceph Storage 6

  All versions: affected

• Red Hat · Red Hat Ceph Storage 6

  All versions: affected

• Red Hat · Red Hat Ceph Storage 8

  All versions: affected

• Red Hat · Red Hat Ceph Storage 8

  All versions: affected

• Red Hat · Red Hat Developer Hub 1

  All versions: affected

• Red Hat · Red Hat Developer Hub 1

  All versions: affected

• Red Hat · Red Hat Edge Manager preview

  All versions: affected

• Red Hat · Red Hat Edge Manager preview

  All versions: affected

• Red Hat · Red Hat Edge Manager preview

  All versions: affected

• Red Hat · Red Hat Edge Manager preview

  All versions: affected

• Red Hat · Red Hat Edge Manager preview

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• Red Hat · Red Hat Edge Manager preview

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• Red Hat · Red Hat Edge Manager preview

  All versions: affected

• Red Hat · Red Hat Edge Manager preview

  All versions: affected

• Red Hat · Red Hat Edge Manager preview

  All versions: affected

• Red Hat · Red Hat Edge Manager preview

  All versions: affected

• Red Hat · Red Hat Enterprise Linux 10

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux 9

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: affected

• Red Hat · Red Hat Enterprise Linux AI (RHEL AI)

  All versions: affected

• Red Hat · Red Hat OpenShift AI (RHOAI)

  All versions: affected

• Red Hat · Red Hat OpenShift AI (RHOAI)

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Container Platform 4

  All versions: affected

• Red Hat · Red Hat OpenShift Dev Workspaces Operator

  All versions: affected

• Red Hat · Red Hat OpenShift Dev Workspaces Operator

  All versions: affected

• Red Hat · Red Hat OpenShift Dev Workspaces Operator

  All versions: affected

• Red Hat · Red Hat OpenShift for Windows Containers

  All versions: affected

• Red Hat · Red Hat OpenShift for Windows Containers

  All versions: affected

• Red Hat · Red Hat OpenShift GitOps

  All versions: affected

• Red Hat · Red Hat OpenShift GitOps

  All versions: affected

• Red Hat · Red Hat OpenShift GitOps

  All versions: affected

• Red Hat · Red Hat OpenShift GitOps

  All versions: affected

• Red Hat · Red Hat OpenShift Virtualization 4

  All versions: affected

• Red Hat · Red Hat OpenStack Platform 16.2

  All versions: unknown

• Red Hat · Red Hat OpenStack Platform 16.2

  All versions: unknown

• Red Hat · Red Hat OpenStack Platform 16.2

  All versions: unknown

• Red Hat · Red Hat OpenStack Platform 17.1

  All versions: unknown

• Red Hat · Red Hat OpenStack Platform 17.1

  All versions: unknown

• Red Hat · Red Hat OpenStack Platform 17.1

  All versions: unknown

• Red Hat · Red Hat Trusted Application Pipeline

  All versions: affected

• Red Hat · Red Hat Trusted Artifact Signer

  All versions: affected

• Red Hat · Red Hat Trusted Artifact Signer

  All versions: affected

• Red Hat · Red Hat Trusted Artifact Signer

  All versions: affected

• Red Hat · Red Hat Trusted Artifact Signer

  All versions: affected

• Red Hat · Red Hat Trusted Artifact Signer

  All versions: affected

• Red Hat · Red Hat Trusted Artifact Signer

  All versions: affected

• Red Hat · Red Hat Trusted Artifact Signer

  All versions: affected

• Red Hat · Red Hat Trusted Artifact Signer

  All versions: affected

• Red Hat · Red Hat Trusted Profile Analyzer

  All versions: affected

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• Gogithub.com/cloudflare/circlGHSA-2x5j-vhc8-9cwm (opens in a new tab)

What to do

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)

• https://access.redhat.com/security/cve/CVE-2025-8556 (opens in a new tab)vdb-entryx_refsource_REDHAT
• RHBZ#2371624 (opens in a new tab)issue-trackingx_refsource_REDHAT
• https://github.com/cloudflare/circl (opens in a new tab)
• https://github.com/cloudflare/circl/security/advisories/GHSA-2x5j-vhc8-9cwm (opens in a new tab)
• https://github.com/cloudflare/circl/tree/v1.6.1 (opens in a new tab)
• https://www.botanica.software/blog/cryptographic-issues-in-cloudflares-circl-fourq-implementation (opens in a new tab)
• https://news.ycombinator.com/item?id=45669593 (opens in a new tab)

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-2x5j-vhc8-9cwm (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2025-8556](https://trackcve.app/badge/CVE-2025-8556.svg)](https://trackcve.app/cve/CVE-2025-8556)

Record last updated 6 Nov 2026, 17:46 UTC.