Threat Intelligence Database

CVE-2026-18353 is a high-severity server-side request forgery (SSRF) vulnerability in Eclipse Foundation's Eclipse CSI - PIA version 0.4.0. The vulnerability arises from improper validation of the unverified 'iss' claim in a JWT token at the /v1/upload/sbom endpoint. Due to inconsistent parsing of URLs containing backslashes by Python's urlparse and the requests library, an attacker can bypass issuer allowlist checks and cause the server to make arbitrary network requests to attacker-controlled hosts.

PIA's OIDC issuer allowlist for Jenkins tokens uses a bare string-prefix check (issuer.startswith(' https://ci.eclipse.org ') in is_issuer_known, pia/models.py:139) instead of validating the issuer as a properly host-bounded URL. An attacker can craft an issuer such as https://[email protected] (userinfo trick) or https://ci.eclipse.org.evil.host (suffix trick) that satisfies the prefix check while pointing the OIDC discovery and JWKS fetches at a server the attacker controls. An unauthenticated caller of POST /v1/upload/sbom can use this to force PIA to make outbound HTTP(S) requests to an arbitrary attacker-chosen host, and to have oidc.verify_token accept a JWT signed with the attacker's own key.

The /v1/upload/sbom endpoint extracts the iss claim from the attacker-supplied JWT with signature verification disabled, then interpolates that string into three log statements before any validation gate. Because the configured log format ("%(asctime)s - %(name)s - %(levelname)s - %(message)s") renders newlines literally, an unauthenticated attacker can forge log records that are byte-for-byte indistinguishable from PIA's genuine "Successfully authenticated project" message. PIA is an authentication broker whose logs are explicitly relied upon for incident response (DESIGN.md §5.4 lists "Token verifications" and "Errors" as events to log), so the ability to plant fake auth-success entries directly undermines the audit trail the service exists to produce.