CVE-2026-22772
Fulcio vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass
MEDIUM 5.3EPSS 0.2%
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.
- Affected
- sigstore · fulcio
- CVSS v3.1 NVD
- 5.3 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - CVSS v3.1 GITHUB
- 5.8 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N - EPSS
- 0.23% chance of exploitation in the next 30 days, 13th percentile
- Published
- 2026-01-12
Proof-of-concept exploits (1)
Security advisories
- sigstore/fulcio/security/advisories/GHSA-59jp-pj84-45mr
- sigstore/fulcio/commit/eaae2f2be56df9dea5f9b439ec81bedae4c0978d