Fulcio vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass
Priority HIGH 65CWE-918Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Partial Red Hat: 3 fixed, 40 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-918 and the CVSS impact.
Summary
Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.5, Fulcio's metaRegex() function uses unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to probe an internal network through Blind SSRF. This vulnerability is fixed in 1.8.5.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00232 14th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial fulcio (sigstore): 1.8.5github.com/sigstore/fulcio (Go): 1.8.5Red Hat: 5 advisoriesRed Hat: 3 fixed, 40 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
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 1.8.5 | 1.8.5 | Patch available | CNA |
| — | github.com/sigstore/fulcio (Go) | before 1.8.5 | 1.8.5 | Patch available | GHSA-59jp-pj84-45mr |
- fulcio Vendorsigstore Affected before 1.8.5 Fixed in 1.8.5 Patch available CNA
- github.com/sigstore/fulcio (Go) Vendor— Affected before 1.8.5 Fixed in 1.8.5 Patch available GHSA-59jp-pj84-45mr
Remediation
- Fix · CNA fulcio (sigstore) Fixed in 1.8.5
- Fix · GHSA-59jp-pj84-45mr github.com/sigstore/fulcio (Go) Fixed in 1.8.5 Advisory →
Red Hat 5 advisories
- RHSA-2026:37387 Released 2026-07-09 · Red Hat rating ImportantRed Hat OpenShift Data Foundation 4.22.0 security, enhancement & bug fix update
- Red Hat Openshift Data Foundation 4.22 registry.redhat.io/odf4/cephcsi-rhel9, registry.redhat.io/odf4/cephcsi-rhel9-operator, registry.redhat.io/odf4/devicefinder-rhel9 +24
- RHSA-2026:2924 Released 2026-02-18 · Red Hat rating ImportantRHTAS 1.2.2 - Red Hat Trusted Artifact Signer Release
- Red Hat Trusted Artifact Signer 1.2 registry.redhat.io/rhtas/client-server-rhel9
- RHSA-2026:2922 Released 2026-02-18 · Red Hat rating ImportantRHTAS 1.2.2 - Red Hat Trusted Artifact Signer Release
- Red Hat Trusted Artifact Signer 1.2 registry.redhat.io/rhtas/cosign-rhel9, registry.redhat.io/rhtas/gitsign-rhel9, registry.redhat.io/rhtas/rekor-cli-rhel9 +1
Show 2 more Red Hat advisories
- RHSA-2026:2144 Released 2026-02-05 · Red Hat rating ImportantRHTAS 1.3.2 - Red Hat Trusted Artifact Signer Release
- Red Hat Trusted Artifact Signer 1.3 registry.redhat.io/rhtas/certificate-transparency-rhel9, registry.redhat.io/rhtas/fulcio-rhel9, registry.redhat.io/rhtas/rekor-backfill-redis-rhel9 +7
- RHSA-2026:2136 Released 2026-02-05 · Red Hat rating ImportantRHTAS 1.3.2 - Red Hat Trusted Artifact Signer Release
- Red Hat Trusted Artifact Signer 1.3 registry.redhat.io/rhtas/cosign-rhel9, registry.redhat.io/rhtas/gitsign-rhel9, registry.redhat.io/rhtas/rekor-cli-rhel9 +1
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 |
| Compliance Operator | Affected | No fix yet: Fix deferred |
| Confidential Compute Attestation | Affected | No fix yet: Fix deferred |
| File Integrity Operator | Affected | No fix yet: Fix deferred |
| Kernel Module Management Operator for Red Hat Openshift | 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: Fix deferred |
| Network Observability Operator | Affected | No fix yet: Fix deferred |
| 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 2 | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 3 | Affected | No fix yet: Fix deferred |
| Power monitoring for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Management for Kubernetes 2 | 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 Build of Kueue | Affected | No fix yet: Fix deferred |
| Red Hat Build of Podman Desktop - Tech Preview | Affected | No fix yet: Fix deferred |
| Red Hat Certification Program for Red Hat Enterprise Linux 9 | 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 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | 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 Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift GitOps | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 18.0 | Affected | No fix yet: Fix deferred |
| Red Hat Quay 3 | Affected | No fix yet: Fix deferred |
| Red Hat Web Terminal | Affected | No fix yet: Fix deferred |
| Security Profiles Operator | Affected | No fix yet: Fix deferred |
| Red Hat Openshift Data Foundation 4.22 | Fixed | RHSA-2026:37387 |
| Red Hat Trusted Artifact Signer 1.2 | Fixed | RHSA-2026:2922, RHSA-2026:2924 |
| Red Hat Trusted Artifact Signer 1.3 | Fixed | RHSA-2026:2136, RHSA-2026:2144 |
Not affected: 3 products
- Red Hat Openshift Data Foundation 4.22
- Red Hat Trusted Artifact Signer 1.2
- Red Hat Trusted Artifact Signer 1.3
Timeline
- 2026-10-02 Threatist record created from CVE-2026-22772
- 2026-10-03 Alias added: GHSA-59jp-pj84-45mr
- 2026-10-27 Affected versions changed · 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-2026-36085 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
- TI-2026-36028 sigstore-js: DSSE payloadType type-binding failure CVSS 3.1MEDIUM 5.4
Sources
- CVE-2026-22772 · CVE Program
- CVE-2026-22772 · NVD
- FIRST EPSS
- GHSA-59jp-pj84-45mr · GitHub Advisory Database · CC BY 4.0
- CVE-2026-22772 · 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