{"id":"GHSA-w5r6-mcgq-7pq4","summary":"Yamcs has No Rate Limiting on Authentication Endpoint","details":"### Summary\n\nThe authentication endpoint `POST /auth/token` in `yamcs-core` lacks any form of rate limiting, account lockout, or failed attempt throttling. As a result, an unauthenticated remote attacker can perform unlimited password guessing attempts against any user account.\n\nThis missing rate limiting vulnerability (CWE-307) significantly increases the risk of successful brute-force attacks.\n\n### Root Cause\n\n**File:** `yamcs-core/src/main/java/org/yamcs/http/auth/AuthHandler.java`\n\n`POST /auth/token` has no rate limiting, no lockout after failed attempts, and no CAPTCHA. The handler processes unlimited authentication requests without any throttling mechanism:\n\n```java\n// AuthHandler.java — handleToken()\n// No throttle, no failed attempt counter, no lockout\nprivate void handleToken(HandlerContext ctx) {\n    ...\n    getSecurityStore().login(token).whenComplete((info, err) -\u003e {\n        // Directly attempts authentication with no rate check\n    });\n}\n```\n\nThis is absent by default — the official quickstart and documentation contain no guidance on configuring rate limiting.\n\n### Impact\n\nAn attacker can make unlimited authentication attempts against any account. This enables efficient brute-force attacks against any account.\n\n### Proof of Concept\n\n```bash\n# 20 attempts — zero rate limiting\nfor i in $(seq 1 20); do\n  curl -s -o /dev/null -w \"Attempt $i: HTTP %{http_code}\\n\" \\\n    -X POST \"http://TARGET:8090/auth/token\" \\\n    -d \"grant_type=password&username=operator&password=operator12$i\"\ndone\n# All return HTTP 401 — no HTTP 429 ever\n```\n\n**Confirmed:** 20 attempts in 0.07 seconds, no rate limiting enforced.\n\n### Fix\n\nImplement DRF-style throttling on `/auth/token`:\n\n```java\n// Track failed attempts per IP\nprivate static final Cache\u003cString, Integer\u003e FAILED_ATTEMPTS =\n    CacheBuilder.newBuilder().expireAfterWrite(15, TimeUnit.MINUTES).build();\n\nprivate static final int MAX_ATTEMPTS = 10;\n\nprivate void handleToken(HandlerContext ctx) {\n    String ip = ctx.getRemoteAddress();\n    int attempts = Optional.ofNullable(FAILED_ATTEMPTS.getIfPresent(ip)).orElse(0);\n    if (attempts \u003e= MAX_ATTEMPTS) {\n        throw new TooManyRequestsException(\"Rate limit exceeded\");\n    }\n    // ... existing auth logic\n    // On failure: FAILED_ATTEMPTS.put(ip, attempts + 1)\n}\n```","aliases":["CVE-2026-44596"],"modified":"2026-05-27T00:26:41.559053Z","published":"2026-05-27T00:04:28Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-05-27T00:04:28Z","nvd_published_at":null,"cwe_ids":["CWE-307"],"severity":"MODERATE"},"references":[{"type":"WEB","url":"https://github.com/yamcs/yamcs/security/advisories/GHSA-w5r6-mcgq-7pq4"},{"type":"PACKAGE","url":"https://github.com/yamcs/yamcs"}],"affected":[{"package":{"name":"org.yamcs:yamcs-core","ecosystem":"Maven","purl":"pkg:maven/org.yamcs/yamcs-core"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.12.7"}]}],"versions":["0.29.3","0.30.0","3.0.0","3.1.0","3.1.1","3.1.2","3.2.0","3.2.1","3.2.2","3.3.0","3.3.1","3.4.0","3.4.1","3.4.11","3.4.2","3.4.3","3.4.4","3.4.5","3.4.6","3.4.8","4.0.0","4.0.1","4.1.1","4.1.2","4.10.0","4.10.1","4.10.2","4.10.3","4.10.4","4.10.5","4.10.6","4.10.7","4.10.8","4.10.9","4.2.0","4.2.1","4.2.2","4.3.0","4.3.1","4.4.0","4.4.1","4.4.2","4.5.0","4.6.0","4.6.1","4.6.2","4.6.3","4.7","4.7.1","4.7.3","4.8.0","4.8.1","4.9.0","4.9.1","4.9.2","4.9.3","4.9.4","5.0.0","5.1.0","5.1.1","5.1.2","5.1.3","5.1.4","5.10.0","5.10.1","5.10.10","5.10.11","5.10.12","5.10.2","5.10.3","5.10.4","5.10.5","5.10.6","5.10.7","5.10.8","5.10.9","5.11.0","5.11.1","5.11.10","5.11.11","5.11.12","5.11.13","5.11.2","5.11.3","5.11.4","5.11.5","5.11.6","5.11.7","5.11.8","5.11.9","5.12.0","5.12.1","5.12.2","5.12.3","5.12.4","5.12.5","5.12.6","5.2.0","5.2.1","5.2.2","5.2.3","5.2.4","5.2.5","5.2.6","5.3.0","5.3.1","5.3.2","5.3.3","5.3.4","5.3.5","5.3.6","5.4.0","5.4.1","5.4.2","5.4.3","5.4.4","5.4.5","5.5.0","5.5.1","5.5.2","5.5.3","5.5.4","5.5.5","5.5.6","5.5.7","5.6.0","5.6.1","5.6.2","5.7.0","5.7.1","5.7.10","5.7.11","5.7.12","5.7.13","5.7.2","5.7.3","5.7.4","5.7.5","5.7.6","5.7.7","5.7.8","5.7.9","5.8.0","5.8.1","5.8.2","5.8.3","5.8.4","5.8.5","5.8.6","5.8.7","5.8.8","5.9.0","5.9.1","5.9.10","5.9.11","5.9.12","5.9.2","5.9.3","5.9.4","5.9.5","5.9.6","5.9.7","5.9.8","5.9.8.1","5.9.9"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-w5r6-mcgq-7pq4/GHSA-w5r6-mcgq-7pq4.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"}]}