DeepWiki-Open EUVD-2026-90439

No special conditions - remote unauthenticated exploitation against default configurations of DeepWiki-Open (through commit d92819a). The only requirements are network reachability of the API and that the /codemap/file endpoint is exposed; exploitation is a single GET request supplying a non-URL repo_url value with an absolute path. The practical limit on impact is that disclosure is bounded to files readable by the API process's user, and the product's small deployment footprint constrains the realistic target population rather than any attacker-side prerequisite.

This is a genuine, high-priority exposure for anyone running DeepWiki-Open, despite the absence of exploitation telemetry. The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:H) describes the most favorable conditions for an attacker: network-reachable, low complexity, no authentication, no user interaction. The flaw is a classic CWE-73 (external control of file name/path) reachable through a single unauthenticated GET request to /codemap/file, so it is trivially automatable against any exposed instance. Impact is scoped correctly to confidentiality only (VC:H, VI:N, VA:N) - it reads arbitrary files but does not by itself write or execute, which is why the 'RCE' tag overstates the technical impact. No EPSS score, no CISA KEV listing, and no confirmed public exploit code were provided; the VulnCheck advisory and GitHub issue #590 document the technique and vulnerable source (codemap.py/repository.py) but that is disclosure, not a weaponized exploit or active-exploitation signal. Net: a high-severity, easily-exploited bug in a low-footprint product - real priority for the small population that runs it (expose secrets, config, SSH keys, source), but not a mass-exploitation event at this time.

An attacker locates an internet-exposed DeepWiki-Open instance and sends an unauthenticated GET /codemap/file request supplying a non-URL value for repo_url (e.g. an absolute path like /etc/passwd or /app/.env). Because the non-URL value bypasses the path-containment check, the API returns the contents of any file readable by the service process, letting the attacker harvest credentials, API keys, and source code. No public exploit code is identified at time of analysis, but the VulnCheck advisory details the exact endpoint and bypass.