CVE-2025-66506

Summary

Fulcio is a free-to-use certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.3, function identity.extractIssuerURL splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request with an (invalid) OIDC identity token in the payload containing many period characters, a call to extractIssuerURL incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. This vulnerability is fixed in 1.8.3.

Affected Software

VendorProductVersion RangeStatus
sigstorefulcio< 1.8.3affected

Weaknesses

  • CWE-405: CWE-405: Asymmetric Resource Consumption (Amplification)

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References