CVE-2026-5538: Qingdaou Onlinejudge

Medium severity, CVSS 6.3. EPSS: 0.3% chance of exploitation in the next 30 days.

A vulnerability was detected in QingdaoU OnlineJudge up to 1.6.1. Affected by this issue is the function service_url of the file JudgeServer.service_url of the component judge_server_heartbeat Endpoint. The manipulation results in server-side request forgery. It is possible to launch the attack remotely. The vendor was contacted early about this disclosure but did not respond in any way.

Affected products

• Qingdaou Onlinejudge: version 1.6.0 only; version 1.6.1 only

Published 2026-04-05. Last modified 2026-07-24.