SSRF in Qingdaou Onlinejudge
CVE-2026-5538
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.003 (26.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Qingdaou Onlinejudge — versions 1.6.0, 1.6.1
Weakness classification (CWE)
References
- vuldb.com/vuln/355291 (technical-description, vdb-entry)
- vuldb.com/vuln/355291/cti (signature, permissions-required)
- vuldb.com/submit/782203 (third-party-advisory)
- github.com/AnalogyC0de/public_exp/issues/27 (issue-tracking)
Frequently asked questions
- What is CVE-2026-5538?
- CVE-2026-5538 is a medium-severity vulnerability in Qingdaou Onlinejudge, classified under Server-Side Request Forgery (SSRF). CVSS score: 6.3/10. Published 2026-04-05.
- How severe is CVE-2026-5538?
- Medium severity. CVSS v3 base score is 6.3 out of 10.