Nezha before 2.3.1 Denial of Service via Concurrent Server Delete

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-101088",
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "dateUpdated": "2026-09-27T20:49:59.487Z",
    "dateReserved": "2026-09-27T20:29:07.432Z",
    "datePublished": "2026-09-27T20:49:59.487Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck",
        "dateUpdated": "2026-09-27T20:49:59.487Z"
      },
      "datePublic": "2026-08-01T00:00:00.000Z",
      "title": "Nezha before 2.3.1 Denial of Service via Concurrent Server Delete",
      "descriptions": [
        {
          "lang": "en",
          "value": "Nezha is a server and website monitoring tool. In versions >= 2.2.11 and < 2.3.1, the service sentinel worker (service/singleton/servicesentinel.go) contains an incomplete fix for a previously reported nil dereference denial of service (GHSA-qjpp-gffx-2wm9). The 2026-07-21 fix re-validated the service lifecycle under serviceResponseDataStoreLock but reused an already-captured, now stale reporter pointer and never re-validated the server, and that lock does not guard ServerShared. An authenticated user with the member role who owns an agent can issue a concurrent server delete (POST /api/v1/batch-delete/server) for their own server to win the race window, causing the worker to dereference a missing entry in the server list snapshot. Because the sentinel workers and the gRPC server have no recover()/recovery interceptor, the resulting panic is unrecovered and crashes the entire instance. This is fixed in version 2.3.1."
        }
      ],
      "affected": [
        {
          "vendor": "nezhahq",
          "product": "nezha",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "2.2.11",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "2.3.1"
            },
            {
              "version": "2.3.1",
              "status": "unaffected",
              "versionType": "semver"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "Time-of-check Time-of-use (TOCTOU) Race Condition",
              "cweId": "CWE-367",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://github.com/nezhahq/nezha/security/advisories/GHSA-jx78-55p5-rwv5",
          "name": "GitHub Security Advisory (GHSA-jx78-55p5-rwv5)",
          "tags": [
            "vendor-advisory"
          ]
        },
        {
          "url": "https://www.vulncheck.com/advisories/nezha-before-2.3.1-denial-of-service-via-concurrent-server-delete",
          "name": "VulnCheck Advisory: Nezha before 2.3.1 Denial of Service via Concurrent Server Delete",
          "tags": [
            "third-party-advisory"
          ]
        }
      ],
      "metrics": [
        {
          "format": "CVSS"
        },
        {
          "format": "CVSS",
          "cvssV3_1": {
            "version": "3.1",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
            "attackVector": "NETWORK",
            "attackComplexity": "HIGH",
            "privilegesRequired": "LOW",
            "userInteraction": "NONE",
            "scope": "UNCHANGED",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "availabilityImpact": "HIGH",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM"
          }
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "arpitjain099",
          "type": "reporter"
        }
      ]
    }
  }
}