CVE-2026-74905 (GCVE-0-2026-74905)
Vulnerability from cvelistv5
Published
2026-08-18 11:19
Modified
2026-08-19 14:10
Severity ?
6.9 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L
7.1 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
CWE
  • CWE-918 - Server-Side Request Forgery (SSRF)
Summary
SiYuan before v3.7.4 contains a server-side request forgery (SSRF) vulnerability in the isPrivateIP function in kernel/util/net.go, used by SSRFSafeDialer to enforce SSRF protection in SafeMode. The function only checks for loopback, link-local unicast, private, and unspecified addresses and does not recognize IPv6 transition addresses (NAT64 64:ff9b::/96, 6to4 2002::/16, Teredo 2001::/32) that embed private IPv4 destinations. When SafeMode is enabled, an authenticated attacker can bypass the SSRF guard via the network forward proxy, WebSocket proxy, or SSE proxy endpoints by supplying a URL whose hostname resolves to such a transition address, reaching internal services and cloud metadata endpoints (e.g., 169.254.169.254). Because the forward proxy returns the full response body, this is a full-read SSRF that can be used to steal instance credentials, reach internal services, and port-scan internal infrastructure.
References
Impacted products
Vendor Product Version
siyuan-note siyuan Version: 0   ≤
Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-74905",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-19T14:09:42.098446Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-19T14:10:27.258Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-qq8m-8p8v-x4xg"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "siyuan",
          "vendor": "siyuan-note",
          "versions": [
            {
              "lessThan": "3.7.4",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "3.7.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "3.7.4",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "datePublic": "2026-08-04T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "SiYuan before v3.7.4 contains a server-side request forgery (SSRF) vulnerability in the isPrivateIP function in kernel/util/net.go, used by SSRFSafeDialer to enforce SSRF protection in SafeMode. The function only checks for loopback, link-local unicast, private, and unspecified addresses and does not recognize IPv6 transition addresses (NAT64 64:ff9b::/96, 6to4 2002::/16, Teredo 2001::/32) that embed private IPv4 destinations. When SafeMode is enabled, an authenticated attacker can bypass the SSRF guard via the network forward proxy, WebSocket proxy, or SSE proxy endpoints by supplying a URL whose hostname resolves to such a transition address, reaching internal services and cloud metadata endpoints (e.g., 169.254.169.254). Because the forward proxy returns the full response body, this is a full-read SSRF that can be used to steal instance credentials, reach internal services, and port-scan internal infrastructure."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "LOW",
            "subConfidentialityImpact": "LOW",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-918",
              "description": "Server-Side Request Forgery (SSRF)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-18T11:19:36.761Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-qq8m-8p8v-x4xg)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-qq8m-8p8v-x4xg"
        },
        {
          "name": "VulnCheck Advisory: SiYuan before v3.7.4 SSRF via IPv6 Transition Address Bypass",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/siyuan-before-ssrf-via-ipv6-transition-address-bypass"
        }
      ],
      "title": "SiYuan before v3.7.4 SSRF via IPv6 Transition Address Bypass",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-74905",
    "datePublished": "2026-08-18T11:19:36.761Z",
    "dateReserved": "2026-08-17T10:48:45.738Z",
    "dateUpdated": "2026-08-19T14:10:27.258Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"cna\": {\"providerMetadata\": {\"orgId\": \"83251b91-4cc7-4094-a5c7-464a1b83ea10\", \"shortName\": \"VulnCheck\", \"dateUpdated\": \"2026-08-18T11:19:36.761Z\"}, \"datePublic\": \"2026-08-04T00:00:00.000Z\", \"title\": \"SiYuan before v3.7.4 SSRF via IPv6 Transition Address Bypass\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"SiYuan before v3.7.4 contains a server-side request forgery (SSRF) vulnerability in the isPrivateIP function in kernel/util/net.go, used by SSRFSafeDialer to enforce SSRF protection in SafeMode. The function only checks for loopback, link-local unicast, private, and unspecified addresses and does not recognize IPv6 transition addresses (NAT64 64:ff9b::/96, 6to4 2002::/16, Teredo 2001::/32) that embed private IPv4 destinations. When SafeMode is enabled, an authenticated attacker can bypass the SSRF guard via the network forward proxy, WebSocket proxy, or SSE proxy endpoints by supplying a URL whose hostname resolves to such a transition address, reaching internal services and cloud metadata endpoints (e.g., 169.254.169.254). Because the forward proxy returns the full response body, this is a full-read SSRF that can be used to steal instance credentials, reach internal services, and port-scan internal infrastructure.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"description\": \"Server-Side Request Forgery (SSRF)\", \"cweId\": \"CWE-918\", \"type\": \"CWE\"}]}], \"affected\": [{\"vendor\": \"siyuan-note\", \"product\": \"siyuan\", \"defaultStatus\": \"unaffected\", \"versions\": [{\"version\": \"0\", \"status\": \"affected\", \"versionType\": \"semver\", \"lessThan\": \"3.7.4\"}, {\"version\": \"3.7.4\", \"status\": \"unaffected\", \"versionType\": \"semver\"}]}], \"cpeApplicability\": [{\"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*\", \"versionEndExcluding\": \"3.7.4\"}]}]}], \"metrics\": [{\"cvssV4_0\": {\"Automatable\": \"NOT_DEFINED\", \"Recovery\": \"NOT_DEFINED\", \"Safety\": \"NOT_DEFINED\", \"attackComplexity\": \"LOW\", \"attackRequirements\": \"NONE\", \"attackVector\": \"NETWORK\", \"baseScore\": 6.9, \"baseSeverity\": \"MEDIUM\", \"exploitMaturity\": \"NOT_DEFINED\", \"privilegesRequired\": \"NONE\", \"providerUrgency\": \"NOT_DEFINED\", \"subAvailabilityImpact\": \"LOW\", \"subConfidentialityImpact\": \"LOW\", \"subIntegrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"valueDensity\": \"NOT_DEFINED\", \"vectorString\": \"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L\", \"version\": \"4.0\", \"vulnAvailabilityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"LOW\", \"vulnerabilityResponseEffort\": \"NOT_DEFINED\"}, \"format\": \"CVSS\"}, {\"cvssV3_1\": {\"attackComplexity\": \"LOW\", \"attackVector\": \"NETWORK\", \"availabilityImpact\": \"NONE\", \"baseScore\": 7.1, \"baseSeverity\": \"HIGH\", \"confidentialityImpact\": \"HIGH\", \"integrityImpact\": \"LOW\", \"privilegesRequired\": \"LOW\", \"scope\": \"UNCHANGED\", \"userInteraction\": \"NONE\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N\", \"version\": \"3.1\"}, \"format\": \"CVSS\"}], \"references\": [{\"url\": \"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-qq8m-8p8v-x4xg\", \"tags\": [\"vendor-advisory\"], \"name\": \"GitHub Security Advisory (GHSA-qq8m-8p8v-x4xg)\"}, {\"name\": \"VulnCheck Advisory: SiYuan before v3.7.4 SSRF via IPv6 Transition Address Bypass\", \"tags\": [\"third-party-advisory\"], \"url\": \"https://www.vulncheck.com/advisories/siyuan-before-ssrf-via-ipv6-transition-address-bypass\"}], \"x_generator\": {\"engine\": \"vulncheck-endgame\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-74905\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-08-19T14:09:42.098446Z\"}}}], \"references\": [{\"url\": \"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-qq8m-8p8v-x4xg\", \"tags\": [\"exploit\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-08-19T14:10:19.084Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-74905\", \"assignerOrgId\": \"83251b91-4cc7-4094-a5c7-464a1b83ea10\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"VulnCheck\", \"dateReserved\": \"2026-08-17T10:48:45.738Z\", \"datePublished\": \"2026-08-18T11:19:36.761Z\", \"dateUpdated\": \"2026-08-19T14:10:27.258Z\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.