CVE-2025-30156 (GCVE-0-2025-30156)

Vulnerability from cvelistv5 – Published: 2026-08-27 20:34 – Updated: 2026-08-27 20:34
VLAI
Title
Ceph: AES-CBC misuse in CephX and RADOSGW enables authentication bypass and credential forgery
Summary
Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the CephX authentication protocol encrypts tickets with AES-128-CBC in an unauthenticated mode that uses a hard-coded initialization vector and no message authentication, allowing an attacker to forge credentials and gain cluster-wide access. Because the ciphertext is malleable and the monitor will encrypt attacker-chosen entity names, an attacker holding one low-privilege key and able to observe CephX traffic can use the monitor as an encryption oracle and splice ciphertext blocks into valid tickets for privileged entities such as Manager, MDS, and OSD. The same lack of authentication also lets an attacker with CephX permissions escalate privileges by flipping a single bit in a service ticket to set its allow_all field to true. This issue is fixed in versions 20.2.4 and 19.2.6.
Severity
8.9 (High)
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
CWE
  • CWE-327 - Use of a Broken or Risky Cryptographic Algorithm
Assigner
References
Impacted products
Vendor Product Version CPE status
ceph ceph Affected: < 19.2.6
Affected: >= 20.0.0, < 20.2.4
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "ceph",
          "vendor": "ceph",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 19.2.6"
            },
            {
              "status": "affected",
              "version": "\u003e= 20.0.0, \u003c 20.2.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the CephX authentication protocol encrypts tickets with AES-128-CBC in an unauthenticated mode that uses a hard-coded initialization vector and no message authentication, allowing an attacker to forge credentials and gain cluster-wide access. Because the ciphertext is malleable and the monitor will encrypt attacker-chosen entity names, an attacker holding one low-privilege key and able to observe CephX traffic can use the monitor as an encryption oracle and splice ciphertext blocks into valid tickets for privileged entities such as Manager, MDS, and OSD. The same lack of authentication also lets an attacker with CephX permissions escalate privileges by flipping a single bit in a service ticket to set its allow_all field to true. This issue is fixed in versions 20.2.4 and 19.2.6."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "ADJACENT_NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 8.9,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-327",
              "description": "CWE-327: Use of a Broken or Risky Cryptographic Algorithm",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T20:34:41.822Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/ceph/ceph/security/advisories/GHSA-7q3q-3975-qw3q",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/ceph/ceph/security/advisories/GHSA-7q3q-3975-qw3q"
        },
        {
          "name": "https://github.com/ceph/ceph/commit/2ba086255de09c8b95177717cc7e9dd4377e2f0f",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ceph/ceph/commit/2ba086255de09c8b95177717cc7e9dd4377e2f0f"
        },
        {
          "name": "https://github.com/ceph/ceph/commit/3078188a7bdd89e2975280f2a906c71c2f6effd6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ceph/ceph/commit/3078188a7bdd89e2975280f2a906c71c2f6effd6"
        }
      ],
      "source": {
        "advisory": "GHSA-7q3q-3975-qw3q",
        "discovery": "UNKNOWN"
      },
      "title": "Ceph: AES-CBC misuse in CephX and RADOSGW enables authentication bypass and credential forgery"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2025-30156",
    "datePublished": "2026-08-27T20:34:41.822Z",
    "dateReserved": "2025-03-17T12:41:42.566Z",
    "dateUpdated": "2026-08-27T20:34:41.822Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-30156",
      "date": "2026-08-28",
      "epss": "0.00093",
      "percentile": "0.00624"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-30156\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-28T00:16:45.557\",\"lastModified\":\"2026-08-28T00:16:45.557\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the CephX authentication protocol encrypts tickets with AES-128-CBC in an unauthenticated mode that uses a hard-coded initialization vector and no message authentication, allowing an attacker to forge credentials and gain cluster-wide access. Because the ciphertext is malleable and the monitor will encrypt attacker-chosen entity names, an attacker holding one low-privilege key and able to observe CephX traffic can use the monitor as an encryption oracle and splice ciphertext blocks into valid tickets for privileged entities such as Manager, MDS, and OSD. The same lack of authentication also lets an attacker with CephX permissions escalate privileges by flipping a single bit in a service ticket to set its allow_all field to true. This issue is fixed in versions 20.2.4 and 19.2.6.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"ceph\",\"product\":\"ceph\",\"versions\":[{\"version\":\"\u003c 19.2.6\",\"status\":\"affected\"},{\"version\":\"\u003e= 20.0.0, \u003c 20.2.4\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L\",\"baseScore\":8.9,\"baseSeverity\":\"HIGH\",\"attackVector\":\"ADJACENT_NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":2.3,\"impactScore\":6.0}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-327\"}]}],\"references\":[{\"url\":\"https://github.com/ceph/ceph/commit/2ba086255de09c8b95177717cc7e9dd4377e2f0f\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/ceph/ceph/commit/3078188a7bdd89e2975280f2a906c71c2f6effd6\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/ceph/ceph/security/advisories/GHSA-7q3q-3975-qw3q\",\"source\":\"security-advisories@github.com\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-27T23:37:34+00:00",
      "cve": "CVE-2025-30156",
      "id": "CVE-2025-30156",
      "initial_release_date": "2025-01-01T00:00:00+00:00",
      "product_status:known_affected": "272",
      "product_status:known_not_affected": "32",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ceph: kernel: Ceph: exploit of hardcoded IVECs, in a misuse of AES, resulting in authentication bypass",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-30156.json",
      "version": "3"
    }
  }
}



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