Security Bulletin
Summary
ulcio prior to 1.8.3 is vulnerable to a Denial-of-Service (DoS) issue where malicious OIDC tokens containing excessive period characters can trigger high memory allocation during parsing. This can affect watsonx.data.
Vulnerability Details
CVEID: CVE-2025-66506
DESCRIPTION: 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.
CWE: CWE-405: Asymmetric Resource Consumption (Amplification)
CVSS Source: security-advisories@github.com
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| watsonx.data | 2.3 |
Remediation/Fixes
The product needs to be installed or upgraded to the latest available level watsonx.data 2.3.1 or watsonx.data on CPD 5.3.1. Installation/upgrade instructions can be found here: https://www.ibm.com/docs/en/software-hub/5.3.x?topic=watsonxdata-installing
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
08 Apr 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
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Document Location
Worldwide
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Document Information
Modified date:
08 April 2026
Initial Publish date:
08 April 2026
UID
ibm17268891