Server-side request forgery in sigstore fulcio
Priority LOW 39CWE-918Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Partial Red Hat: 2 fixed, 36 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.
Summary
Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Versions through 1.8.5 improperly follow cross-host redirects and attach Kubernetes ServiceAccount tokens during OIDC discovery, allowing a malicious or compromised issuer to perform blind SSRF, substitute and cache malicious JWKS keys, or disclose ServiceAccount tokens to external hosts. Version 1.8.6 blocks cross-host redirects, restricts token injection, and restricts local token loading. No known workarounds are available.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00282 20th percentileScored 2026-11-07
Fix Partial fulcio (sigstore): 1.8.6github.com/sigstore/fulcio (Go): 1.8.6Red Hat: 2 advisoriesRed Hat: 2 fixed, 36 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| sigstore | fulcio | before 1.8.6 | 1.8.6 | Patch available | CNA |
| — | github.com/sigstore/fulcio (Go) | before 1.8.6 | 1.8.6 | Patch available | GHSA-f5mr-q85p-6hh6 |
- fulcio Vendorsigstore Affected before 1.8.6 Fixed in 1.8.6 Patch available CNA
- github.com/sigstore/fulcio (Go) Vendor— Affected before 1.8.6 Fixed in 1.8.6 Patch available GHSA-f5mr-q85p-6hh6
Remediation
- Fix · CNA fulcio (sigstore) Fixed in 1.8.6
- Fix · GHSA-f5mr-q85p-6hh6 github.com/sigstore/fulcio (Go) Fixed in 1.8.6 Advisory →
Red Hat 2 advisories
- RHSA-2026:48913 Released 2026-07-30 · Red Hat rating ImportantRHACS 4.10.6 security and bug fix update
- Red Hat Advanced Cluster Security for Kubernetes for IBM Power, little endian 4.10 registry.redhat.io/advanced-cluster-security/rhacs-main-rhel8, registry.redhat.io/advanced-cluster-security/rhacs-rhel8-operator
- RHSA-2026:48872 Released 2026-07-30 · Red Hat rating ImportantRHACS 4.9.10 security and bug fix update
- Red Hat Advanced Cluster Security 4.9 registry.redhat.io/advanced-cluster-security/rhacs-main-rhel8, registry.redhat.io/advanced-cluster-security/rhacs-rhel8-operator, registry.redhat.io/advanced-cluster-security/rhacs-scanner-v4-rhel8
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Assisted Installer for Red Hat OpenShift Container Platform 2 | Affected | No fix yet: Fix deferred |
| Confidential Compute Attestation | Affected | No fix yet: Fix deferred |
| Kernel Module Management Operator for Red Hat Openshift | Affected | No fix yet: Fix deferred |
| Lightspeed Core | Affected | No fix yet: Fix deferred |
| Logging Subsystem for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Logical Volume Manager Storage | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Containers | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Virtualization | Affected | No fix yet: Fix deferred |
| Multiarch Tuning Operator | Affected | No fix yet: Fix deferred |
| Multicluster Engine for Kubernetes | Affected | No fix yet |
| Node HealthCheck Operator | Affected | No fix yet: Fix deferred |
| OpenShift API for Data Protection | Affected | No fix yet: Fix deferred |
| OpenShift Developer Tools and Services | Affected | No fix yet: Fix deferred |
| OpenShift Lightspeed | Affected | No fix yet: Fix deferred |
| OpenShift Pipelines | Affected | No fix yet: Fix deferred |
| OpenShift Serverless | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 3 | Affected | No fix yet: Fix deferred |
| Pen Drive Powered by Red Hat Lightspeed | Affected | No fix yet: Fix deferred |
| Power monitoring for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Security 4 | Affected | No fix yet: Fix deferred |
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat Developer Hub 1 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift GitOps | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Virtualization 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 18.0 | Affected | No fix yet: Fix deferred |
| Red Hat Openshift Data Foundation 4 | Affected | No fix yet: Fix deferred |
| Red Hat Quay 3 | Affected | No fix yet: Fix deferred |
| Red Hat Trusted Artifact Signer | Affected | No fix yet: Fix deferred |
| Security Profiles Operator | Affected | No fix yet: Fix deferred |
| Self-service automation portal 2 | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Security 4.9 | Fixed | RHSA-2026:48872 |
| Red Hat Advanced Cluster Security for Kubernetes for IBM Power, little endian 4.10 | Fixed | RHSA-2026:48913 |
Not affected: 39 products
- Assisted Installer for Red Hat OpenShift Container Platform 2
- Confidential Compute Attestation
- Kernel Module Management Operator for Red Hat Openshift
- Lightspeed Core
- Logging Subsystem for Red Hat OpenShift
- Logical Volume Manager Storage
- Migration Toolkit for Containers
- Migration Toolkit for Virtualization
- Multiarch Tuning Operator
- Multicluster Engine for Kubernetes
- Node HealthCheck Operator
- OpenShift API for Data Protection
- OpenShift Developer Tools and Services
- OpenShift Lightspeed
- OpenShift Pipelines
- OpenShift Serverless
- OpenShift Service Mesh 3
- Pen Drive Powered by Red Hat Lightspeed
- Power monitoring for Red Hat OpenShift
- Red Hat Advanced Cluster Management for Kubernetes 2
- Red Hat Advanced Cluster Security 4
- Red Hat Advanced Cluster Security 4.9
- Red Hat Advanced Cluster Security for Kubernetes for IBM Power, little endian 4.10
- Red Hat Ansible Automation Platform 2
- Red Hat Build of Podman Desktop
- Red Hat Developer Hub 1
- Red Hat Hardened Images
- Red Hat OpenShift AI (RHOAI)
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
- Red Hat OpenShift Dev Spaces
- Red Hat OpenShift GitOps
- Red Hat OpenShift Virtualization 4
- Red Hat OpenStack Platform 18.0
- Red Hat Openshift Data Foundation 4
- Red Hat Quay 3
- Red Hat Trusted Artifact Signer
- Security Profiles Operator
- Self-service automation portal 2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-49478
- 2026-10-03 Alias added: GHSA-f5mr-q85p-6hh6
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
- 2026-11-06 Fix available: Red Hat Advanced Cluster Security for Kubernetes for IBM Power, little endian 4.10 · Red Hat
References
More sigstore vulnerabilities
- TI-2022-16356 False positive signature verification in cosign CVSS 3.1CRITICAL 9.8
- TI-2026-36084 sigstore-js: `certificateOIDs` verification constraints are silently dropped and never enforced CVSS 3.1HIGH 7.5
- TI-2024-19670 Cosign vulnerable to machine-wide denial of service via malicious artifacts CVSS 3.1HIGH 7.5
- TI-2026-18290 Fulcio vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass CVSS 3.1MEDIUM 5.8
- TI-2026-36085 sigstore-js: Insufficient Verification of Data Authenticity CVSS 3.1MEDIUM 6.5
- TI-2024-19669 Cosign vulnerable to system-wide denial of service via malicious attachments CVSS 3.1MEDIUM 5.9
Sources
- CVE-2026-49478 · CVE Program
- CVE-2026-49478 · NVD
- FIRST EPSS
- GHSA-f5mr-q85p-6hh6 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-49478 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences