3proxy 0.9.7 - 1.0.1 Uninitialized Stack Memory Disclosure via SOCKS4

{
  "id": "641d52bf3d9a38f770f2d17a45ae500c29acda930f25cea01335b973de039780",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-109438",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "3proxy 0.9.7 - 1.0.1 Uninitialized Stack Memory Disclosure via SOCKS4",
    "summary": "3proxy from 0.9.7 through 1.0.1, fixed in commit 206c923, contains an uninitialized stack memory disclosure vulnerability that allows unauthenticated attackers to leak stack bytes via the SOCKS4 reply path when the external-NAT option (-Ne) is configured. Attackers can send a client probe that fails the SOCKS version check to trigger a reply containing uninitialized bytes from the sin structure, exposing high bytes of a userspace pointer that weakens ASLR protections.",
    "evidence": "cve:CVE-2026-109438",
    "products": [
      {
        "name": {
          "value": "3proxy",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-109438",
      "aliases": [
        "CVE-2026-109438"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "Safety": "NOT_DEFINED",
            "version": "4.0",
            "Recovery": "NOT_DEFINED",
            "baseScore": 6.3,
            "Automatable": "NOT_DEFINED",
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
            "exploitMaturity": "NOT_DEFINED",
            "providerUrgency": "NOT_DEFINED",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
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        {
          "format": "CVSS",
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 5.3,
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
            "integrityImpact": "NONE",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "availabilityImpact": "NONE",
            "privilegesRequired": "NONE",
            "confidentialityImpact": "LOW"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "affected": [
        {
          "repo": "https://github.com/3proxy/3proxy",
          "vendor": "3proxy",
          "product": "3proxy",
          "versions": [
            {
              "status": "affected",
              "version": "0.9.7",
              "versionType": "semver",
              "lessThanOrEqual": "1.0.1"
            },
            {
              "status": "unaffected",
              "version": "206c923d6cd433bd2e7196375442650c328b8bfa",
              "versionType": "git"
            }
          ],
          "packageURL": "pkg:github/3proxy/3proxy",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-27T01:30:42.993Z",
      "provider": "cve",
      "references": [
        "https://github.com/3proxy/3proxy/commit/206c923d6cd433bd2e7196375442650c328b8bfa",
        "https://www.vulncheck.com/advisories/3proxy-uninitialized-stack-memory-disclosure-via-socks4"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-109438",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-15T19:01:44.310730Z"
                  }
                }
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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              "dateUpdated": "2026-10-15T19:02:26.057Z"
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        "cna": {
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          "shortName": "VulnCheck",
          "dateUpdated": "2026-10-27T01:30:42.993Z"
        }
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    },
    "related_cves": [
      {
        "value": "CVE-2026-109438",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 374647,
  "published_at": "2026-10-14T15:53:36.065+00:00"
}