The flaw arises from a simplistic string‑prefix comparison of OIDC issuer URLs in PIA, where the code checks only that the issuer starts with the prefix "https://ci.eclipse.org". Because the check does not enforce strict host‑bound validation, attackers can forge issuers such as "https://ci.eclipse.org@evil.host" or "https://ci.eclipse.org.evil.host" that satisfy the prefix test while directing the server to an attacker‑controlled discovery or JWKS endpoint. When a caller uses the exposed POST /v1/upload/sbom endpoint, PIA accepts the forged issuer, retrieves keys from the malicious server, and validates a JWT signed with the attacker’s key. It then proceeds to execute the request, effectively impersonating an authorized user and granting the attacker the ability to command artifact uploads and trigger outbound operations.

All released versions of Eclipse CSI PIA before the issuance of the patch are potentially affected. The vulnerability impacts the PIA component provided by the Eclipse Foundation and any environment that hosts PIA without applying the corrected issuer validation logic.

The reported CVSS score of 8.2 indicates a high severity impact on confidentiality and integrity. Although the EPSS score is below 1% KEV catalog, exploitation remains possible through the public, unauthenticated POST /v1/upload/sbom endpoint. Successful exploitation forces PIA to perform arbitrary outbound HTTPS requests to a host of the attacker’s choice and to accept JWTs signed with the attacker’s private key, thereby enabling impersonation and potential data exfiltration or further internal moves.