CVE-2026-22772
MediumCVSS 5.8Summary
Prior to 1.8.5, Fulcio's metaRegex() function uses an unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. The SSRF can only trigger GET requests, cannot mutate state, and the response is not returned, so only blind SSRF is possible.
Risk Assessment
An attacker may probe the organization's internal network (blind SSRF), potentially revealing infrastructure information.
Recommendation
Update Fulcio to version 1.8.5 or later.
Other vulnerabilities in Fulcio
See all- CVE-2026-49478High
Fulcio, a certificate authority for issuing code signing certificates for OIDC identities, 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.
- CVE-2025-66506High
Fulcio prior to 1.8.3 contains a vulnerability in the identity.extractIssuerURL function, which splits its untrusted argument on periods. A malicious request with an invalid OIDC identity token containing many period characters causes allocations of O(n) bytes, where n is the argument length, with a constant factor of about 16.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS