SB2025121628 - Denial of service in Fulcio

Description

This security bulletin contains information about 1 vulnerability.

1) Resource exhaustion (CVE-ID: CVE-2025-66506)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to application does not properly control consumption of internal resources within the identity.extractIssuerURL() function when parsing untrusted arguments. A remote attacker can pass a specially crafted request with a malicious OIDC identity token to trigger resource exhaustion and perform a denial of service (DoS) attack.

Remediation

Install update from vendor's website.

References

• https://github.com/sigstore/fulcio/commit/765a0e57608b9ef390e1eeeea8595b9054c63a5a
• https://github.com/sigstore/fulcio/security/advisories/GHSA-f83f-xpx7-ffpw