CVE-2026-44596: Yamcs core Yamcs Has No Rate Limiting Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-w5r6-mcgq-7pq4",
  "modified" : "2026-05-27T00:04:28Z",
  "published" : "2026-05-27T00:04:28Z",
  "aliases" : [ "CVE-2026-44596" ],
  "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) -> {\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<String, Integer> 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 >= 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```",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.yamcs:yamcs-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.12.7"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/yamcs/yamcs/security/advisories/GHSA-w5r6-mcgq-7pq4"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/yamcs/yamcs"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-307" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-27T00:04:28Z",
    "nvd_published_at" : null
  }
}