CVE-2026-18353 Unauthenticated SSRF in PIA via OIDC issuer allowlist bypass
An unauthenticated attacker can bypass issuer allowlists via URL parsing discrepancies to perform Server-Side Request Forgery against arbitrary hosts.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-18353?
CVE-2026-18353 is a high-severity server-side request forgery vulnerability in Eclipse CSI - PIA, published on 30 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
PIA's `POST /v1/upload/sbom` endpoint accepts a Bearer JWT and checks its **unverified** `iss` claim against an issuer allowlist using Python's `urlparse` before performing OIDC discovery with `requests`. Because `urlparse` and `requests`/`urllib3` parse an authority string containing a backslash (e.g. `https://attacker-host\@ci.eclipse.org/`) into *different* hostnames, an attacker can craft an issuer that passes the allowlist check yet drives `requests` — and subsequently `urllib.request.urlopen` for JWKS retrieval — to connect to an arbitrary attacker-chosen host, port, and scheme.
Weakness: CWE-918
Which versions are affected by CVE-2026-18353?
How do I fix CVE-2026-18353?
No fix has been published for CVE-2026-18353 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-18353 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18353 exists.
Sources
Also known as GHSA-v249-9xjm-qhgf.