CVE-2026-54330 (GCVE-0-2026-54330)

Vulnerability from cvelistv5 – Published: 2026-08-27 20:59 – Updated: 2026-08-28 15:57
VLAI
Title
Ceph RGW SigV4 handler accepts unsigned x-amz-* headers on presigned requests, allowing privilege escalation
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 Ceph Object Gateway (RGW) SigV4 handler does not reject requests that carry x-amz-* headers absent from the signed header set, allowing anyone holding a presigned URL to attach arbitrary unsigned x-amz-* headers that RGW will honor. AWS S3 requires every x-amz-* header on a SigV4 request to be signed and rejects requests bearing additional unsigned headers, but RGW validates only the headers listed in X-Amz-SignedHeaders and ignores any extra ones, so they take effect without being covered by the signature. By adding such headers to a presigned PUT URL, an attacker can grant themselves more capabilities than the URL's signer intended and escalate their privileges. This issue is fixed in versions 20.2.4 and 19.2.6.
Severity
8.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-28 15:45 UTC
CWE
  • CWE-347 - Improper Verification of Cryptographic Signature
Assigner
References
Impacted products
Vendor Product Version CPE status
ceph ceph Affected: >= 19.0.0, < 19.2.6
Affected: >= 20.0.0, < 20.2.4
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-54330",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-28T15:45:40.069617Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-28T15:57:33.424Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "ceph",
          "vendor": "ceph",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 19.0.0, \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 Ceph Object Gateway (RGW) SigV4 handler does not reject requests that carry x-amz-* headers absent from the signed header set, allowing anyone holding a presigned URL to attach arbitrary unsigned x-amz-* headers that RGW will honor. AWS S3 requires every x-amz-* header on a SigV4 request to be signed and rejects requests bearing additional unsigned headers, but RGW validates only the headers listed in X-Amz-SignedHeaders and ignores any extra ones, so they take effect without being covered by the signature. By adding such headers to a presigned PUT URL, an attacker can grant themselves more capabilities than the URL\u0027s signer intended and escalate their privileges. This issue is fixed in versions 20.2.4 and 19.2.6."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-347",
              "description": "CWE-347: Improper Verification of Cryptographic Signature",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T20:59:24.688Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj"
        },
        {
          "name": "https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7"
        },
        {
          "name": "https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a"
        }
      ],
      "source": {
        "advisory": "GHSA-rmjq-ffrm-j6vj",
        "discovery": "UNKNOWN"
      },
      "title": "Ceph RGW SigV4 handler accepts unsigned x-amz-* headers on presigned requests, allowing privilege escalation"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54330",
    "datePublished": "2026-08-27T20:59:24.688Z",
    "dateReserved": "2026-06-12T18:42:02.224Z",
    "dateUpdated": "2026-08-28T15:57:33.424Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-54330",
      "date": "2026-08-28",
      "epss": "0.00181",
      "percentile": "0.07755"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-54330\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-28T00:18:07.683\",\"lastModified\":\"2026-08-28T20:18:16.710\",\"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 Ceph Object Gateway (RGW) SigV4 handler does not reject requests that carry x-amz-* headers absent from the signed header set, allowing anyone holding a presigned URL to attach arbitrary unsigned x-amz-* headers that RGW will honor. AWS S3 requires every x-amz-* header on a SigV4 request to be signed and rejects requests bearing additional unsigned headers, but RGW validates only the headers listed in X-Amz-SignedHeaders and ignores any extra ones, so they take effect without being covered by the signature. By adding such headers to a presigned PUT URL, an attacker can grant themselves more capabilities than the URL\u0027s signer intended and escalate their privileges. 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\":\"\u003e= 19.0.0, \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:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N\",\"baseScore\":8.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.8,\"impactScore\":5.2}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-08-28T15:45:40.069617Z\",\"id\":\"CVE-2026-54330\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"total\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-347\"}]}],\"references\":[{\"url\":\"https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj\",\"source\":\"security-advisories@github.com\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-27T23:37:43+00:00",
      "cve": "CVE-2026-54330",
      "id": "CVE-2026-54330",
      "initial_release_date": "2026-08-19T17:57:46+00:00",
      "product_status:known_affected": "195",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "ceph: ceph: RGW SigV4 verifier allows attachment of arbitrary unsigned x-amz-* headers leading to privilege escalation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-54330.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-54330\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-08-28T15:45:40.069617Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-08-28T15:45:41.151Z\"}}], \"cna\": {\"title\": \"Ceph RGW SigV4 handler accepts unsigned x-amz-* headers on presigned requests, allowing privilege escalation\", \"source\": {\"advisory\": \"GHSA-rmjq-ffrm-j6vj\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 8.1, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"ceph\", \"product\": \"ceph\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003e= 19.0.0, \u003c 19.2.6\"}, {\"status\": \"affected\", \"version\": \"\u003e= 20.0.0, \u003c 20.2.4\"}]}], \"references\": [{\"url\": \"https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj\", \"name\": \"https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7\", \"name\": \"https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a\", \"name\": \"https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a\", \"tags\": [\"x_refsource_MISC\"]}], \"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 Ceph Object Gateway (RGW) SigV4 handler does not reject requests that carry x-amz-* headers absent from the signed header set, allowing anyone holding a presigned URL to attach arbitrary unsigned x-amz-* headers that RGW will honor. AWS S3 requires every x-amz-* header on a SigV4 request to be signed and rejects requests bearing additional unsigned headers, but RGW validates only the headers listed in X-Amz-SignedHeaders and ignores any extra ones, so they take effect without being covered by the signature. By adding such headers to a presigned PUT URL, an attacker can grant themselves more capabilities than the URL\u0027s signer intended and escalate their privileges. This issue is fixed in versions 20.2.4 and 19.2.6.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-347\", \"description\": \"CWE-347: Improper Verification of Cryptographic Signature\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-08-27T20:59:24.688Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-54330\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-28T15:57:33.424Z\", \"dateReserved\": \"2026-06-12T18:42:02.224Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-08-27T20:59:24.688Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.