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.
Fix
Patch, vendor advisory and mitigation references on NVD 2
- https://github.com/sigstore/fulcio/commit/765a0e57608b9ef390e1eeeea8595b9054c63a5a Patch
- https://github.com/sigstore/fulcio/security/advisories/GHSA-f83f-xpx7-ffpw Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.5 · linuxfoundationNVD modified 2026-10-18 15:10
Affected (CPE criteria) 1
cpe:2.3:a:linuxfoundation:fulcio:*:*:*:*:*:*:*:*