cve.bz

CVE-2025-66506

7.5 highEPSS 0.2%

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.

CVSS 3.1
7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
0.2% chance of exploitation in the next 30 days; higher than 11% of CVEs (scores of 2026-10-25)
CWE
CWE-405
Published
Modified
Record from
the NVD, synced

Affected

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-f83f-xpx7-ffpwGogithub.com/sigstore/fulcio<1.8.31.8.3
GO-2025-4193Gogithub.com/sigstore/fulcio<1.8.31.8.3

References

Check your stackJSON