CVE-2026-22772: sigstore fulcio · Server-Side Request Forgery (SSRF)
Affects sigstore fulcioSource CVE Database V5
Not known to be exploited · CVSS 5.8 Medium : upgrade to 1.8.5 when convenient.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.8.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 12 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Upgrade fulcio and sigstore/fulcio to 1.8.5.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| sigstorefulcio | Affected
| Fixed in
|
GitHubsigstore/fulciopkg:github/sigstore/fulcioOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
European organizations should take the following specific steps to mitigate this vulnerability: 1) Upgrade fulcio to version 1.8.5 or later immediately to apply the patch that fixes the unanchored regex validation. 2) Review and restrict network access controls to limit fulcio server outbound HTTP requests only to trusted and necessary destinations, minimizing the attack surface for SSRF. 3) Implement internal network segmentation and firewall rules to reduce the exposure of sensitive internal services that could be probed via SSRF. 4) Monitor fulcio server logs for unusual outbound HTTP requests that could indicate exploitation attempts. 5) Conduct internal security assessments and penetration tests focusing on SSRF and related vulnerabilities within the software supply chain infrastructure. 6) Educate development and DevOps teams about secure configuration and the risks of SSRF in certificate authorities and related components. 7) Consider deploying Web Application Firewalls (WAFs) or SSRF-specific detection mechanisms to detect and block suspicious request patterns targeting fulcio endpoints. 8) Maintain an inventory of all fulcio deployments and ensure consistent patch management across all environments to prevent vulnerable versions from persisting.
Description
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.