CVE-2026-39836 (GCVE-0-2026-39836)

Vulnerability from cvelistv5 – Published: 2026-05-07 19:41 – Updated: 2026-05-08 21:30
VLAI
Title
Panic in Dial and LookupPort when handling NUL byte on Windows in net
Summary
The Dial and LookupPort functions panic on Windows when provided with an input containing a NUL (0).
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
Assigner
Go
References
Impacted products
Vendor Product Version
Go standard library net Affected: 0 , < 1.25.10 (semver)
Affected: 1.26.0-0 , < 1.26.3 (semver)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 7.5,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-39836",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-08T16:36:25.079035Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-08T21:30:15.127Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "packageName": "net",
          "product": "net",
          "programRoutines": [
            {
              "name": "Resolver.lookupPort"
            },
            {
              "name": "Resolver.lookupAddr"
            },
            {
              "name": "Resolver.lookupTXT"
            },
            {
              "name": "Resolver.lookupNS"
            },
            {
              "name": "Resolver.lookupMX"
            },
            {
              "name": "Resolver.lookupSRV"
            },
            {
              "name": "Dial"
            },
            {
              "name": "DialTimeout"
            },
            {
              "name": "Dialer.Dial"
            },
            {
              "name": "Dialer.DialContext"
            },
            {
              "name": "Listen"
            },
            {
              "name": "ListenConfig.Listen"
            },
            {
              "name": "ListenConfig.ListenPacket"
            },
            {
              "name": "ListenPacket"
            },
            {
              "name": "LookupAddr"
            },
            {
              "name": "LookupCNAME"
            },
            {
              "name": "LookupHost"
            },
            {
              "name": "LookupIP"
            },
            {
              "name": "LookupMX"
            },
            {
              "name": "LookupNS"
            },
            {
              "name": "LookupPort"
            },
            {
              "name": "LookupSRV"
            },
            {
              "name": "LookupTXT"
            },
            {
              "name": "ResolveIPAddr"
            },
            {
              "name": "ResolveTCPAddr"
            },
            {
              "name": "ResolveUDPAddr"
            },
            {
              "name": "Resolver.LookupAddr"
            },
            {
              "name": "Resolver.LookupCNAME"
            },
            {
              "name": "Resolver.LookupHost"
            },
            {
              "name": "Resolver.LookupIP"
            },
            {
              "name": "Resolver.LookupIPAddr"
            },
            {
              "name": "Resolver.LookupMX"
            },
            {
              "name": "Resolver.LookupNS"
            },
            {
              "name": "Resolver.LookupNetIP"
            },
            {
              "name": "Resolver.LookupPort"
            },
            {
              "name": "Resolver.LookupSRV"
            },
            {
              "name": "Resolver.LookupTXT"
            }
          ],
          "vendor": "Go standard library",
          "versions": [
            {
              "lessThan": "1.25.10",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.26.3",
              "status": "affected",
              "version": "1.26.0-0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The Dial and LookupPort functions panic on Windows when provided with an input containing a NUL (0)."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-248: Uncaught Exception",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-07T19:41:18.300Z",
        "orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
        "shortName": "Go"
      },
      "references": [
        {
          "url": "https://go.dev/issue/79006"
        },
        {
          "url": "https://groups.google.com/g/golang-announce/c/qcCIEXso47M"
        },
        {
          "url": "https://go.dev/cl/775320"
        },
        {
          "url": "https://pkg.go.dev/vuln/GO-2026-4971"
        }
      ],
      "title": "Panic in Dial and LookupPort when handling NUL byte on Windows in net"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
    "assignerShortName": "Go",
    "cveId": "CVE-2026-39836",
    "datePublished": "2026-05-07T19:41:18.300Z",
    "dateReserved": "2026-04-07T18:13:03.529Z",
    "dateUpdated": "2026-05-08T21:30:15.127Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-39836",
      "date": "2026-07-31",
      "epss": "0.00588",
      "percentile": "0.44786"
    },
    "microsoft_vex": {
      "current_release_date": "2026-06-09T01:42:39.000Z",
      "cve": "CVE-2026-39836",
      "id": "msrc_CVE-2026-39836",
      "initial_release_date": "2026-05-02T00:00:00.000Z",
      "product_status:known_affected": "3",
      "product_status:known_not_affected": "4",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Panic in Dial and LookupPort when handling NUL byte on Windows in net",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-39836.json",
      "version": "6"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-39836\",\"sourceIdentifier\":\"security@golang.org\",\"published\":\"2026-05-07T20:16:43.593\",\"lastModified\":\"2026-06-17T10:42:40.340\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"The Dial and LookupPort functions panic on Windows when provided with an input containing a NUL (0).\"}],\"affected\":[{\"source\":\"security@golang.org\",\"affectedData\":[{\"vendor\":\"Go standard library\",\"product\":\"net\",\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://pkg.go.dev\",\"packageName\":\"net\",\"programRoutines\":[{\"name\":\"Resolver.lookupPort\"},{\"name\":\"Resolver.lookupAddr\"},{\"name\":\"Resolver.lookupTXT\"},{\"name\":\"Resolver.lookupNS\"},{\"name\":\"Resolver.lookupMX\"},{\"name\":\"Resolver.lookupSRV\"},{\"name\":\"Dial\"},{\"name\":\"DialTimeout\"},{\"name\":\"Dialer.Dial\"},{\"name\":\"Dialer.DialContext\"},{\"name\":\"Listen\"},{\"name\":\"ListenConfig.Listen\"},{\"name\":\"ListenConfig.ListenPacket\"},{\"name\":\"ListenPacket\"},{\"name\":\"LookupAddr\"},{\"name\":\"LookupCNAME\"},{\"name\":\"LookupHost\"},{\"name\":\"LookupIP\"},{\"name\":\"LookupMX\"},{\"name\":\"LookupNS\"},{\"name\":\"LookupPort\"},{\"name\":\"LookupSRV\"},{\"name\":\"LookupTXT\"},{\"name\":\"ResolveIPAddr\"},{\"name\":\"ResolveTCPAddr\"},{\"name\":\"ResolveUDPAddr\"},{\"name\":\"Resolver.LookupAddr\"},{\"name\":\"Resolver.LookupCNAME\"},{\"name\":\"Resolver.LookupHost\"},{\"name\":\"Resolver.LookupIP\"},{\"name\":\"Resolver.LookupIPAddr\"},{\"name\":\"Resolver.LookupMX\"},{\"name\":\"Resolver.LookupNS\"},{\"name\":\"Resolver.LookupNetIP\"},{\"name\":\"Resolver.LookupPort\"},{\"name\":\"Resolver.LookupSRV\"},{\"name\":\"Resolver.LookupTXT\"}],\"versions\":[{\"version\":\"0\",\"lessThan\":\"1.25.10\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"1.26.0-0\",\"lessThan\":\"1.26.3\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-05-08T16:36:25.079035Z\",\"id\":\"CVE-2026-39836\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-476\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"1.25.10\",\"matchCriteriaId\":\"1C966EF3-C51C-4239-B5FC-C44A5202FEC8\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"1.26.0\",\"versionEndExcluding\":\"1.26.3\",\"matchCriteriaId\":\"522E4CD0-2B99-4363-9C78-0BAFD988A2D6\"}]}]}],\"references\":[{\"url\":\"https://go.dev/cl/775320\",\"source\":\"security@golang.org\",\"tags\":[\"Patch\"]},{\"url\":\"https://go.dev/issue/79006\",\"source\":\"security@golang.org\",\"tags\":[\"Issue Tracking\"]},{\"url\":\"https://groups.google.com/g/golang-announce/c/qcCIEXso47M\",\"source\":\"security@golang.org\",\"tags\":[\"Issue Tracking\",\"Mailing List\"]},{\"url\":\"https://pkg.go.dev/vuln/GO-2026-4971\",\"source\":\"security@golang.org\",\"tags\":[\"Vendor Advisory\"]}]}}",
    "redhat_vex": {
      "current_release_date": "2026-06-05T19:44:52+00:00",
      "cve": "CVE-2026-39836",
      "id": "CVE-2026-39836",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "Panic in Dial and LookupPort when handling NUL byte on Windows in net",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39836.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-07-15T05:16:09Z",
      "cve": "CVE-2026-39836",
      "id": "CVE-2026-39836",
      "initial_release_date": "2026-05-09T02:43:15Z",
      "product_status:first_fixed": "6",
      "product_status:known_affected": "67",
      "product_status:known_not_affected": "51",
      "product_status:recommended": "258",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-39836",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-39836.json",
      "version": "7"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-39836\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-05-08T16:36:25.079035Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-05-08T16:44:57.022Z\"}}], \"cna\": {\"title\": \"Panic in Dial and LookupPort when handling NUL byte on Windows in net\", \"affected\": [{\"vendor\": \"Go standard library\", \"product\": \"net\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"1.25.10\", \"versionType\": \"semver\"}, {\"status\": \"affected\", \"version\": \"1.26.0-0\", \"lessThan\": \"1.26.3\", \"versionType\": \"semver\"}], \"packageName\": \"net\", \"collectionURL\": \"https://pkg.go.dev\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"Resolver.lookupPort\"}, {\"name\": \"Resolver.lookupAddr\"}, {\"name\": \"Resolver.lookupTXT\"}, {\"name\": \"Resolver.lookupNS\"}, {\"name\": \"Resolver.lookupMX\"}, {\"name\": \"Resolver.lookupSRV\"}, {\"name\": \"Dial\"}, {\"name\": \"DialTimeout\"}, {\"name\": \"Dialer.Dial\"}, {\"name\": \"Dialer.DialContext\"}, {\"name\": \"Listen\"}, {\"name\": \"ListenConfig.Listen\"}, {\"name\": \"ListenConfig.ListenPacket\"}, {\"name\": \"ListenPacket\"}, {\"name\": \"LookupAddr\"}, {\"name\": \"LookupCNAME\"}, {\"name\": \"LookupHost\"}, {\"name\": \"LookupIP\"}, {\"name\": \"LookupMX\"}, {\"name\": \"LookupNS\"}, {\"name\": \"LookupPort\"}, {\"name\": \"LookupSRV\"}, {\"name\": \"LookupTXT\"}, {\"name\": \"ResolveIPAddr\"}, {\"name\": \"ResolveTCPAddr\"}, {\"name\": \"ResolveUDPAddr\"}, {\"name\": \"Resolver.LookupAddr\"}, {\"name\": \"Resolver.LookupCNAME\"}, {\"name\": \"Resolver.LookupHost\"}, {\"name\": \"Resolver.LookupIP\"}, {\"name\": \"Resolver.LookupIPAddr\"}, {\"name\": \"Resolver.LookupMX\"}, {\"name\": \"Resolver.LookupNS\"}, {\"name\": \"Resolver.LookupNetIP\"}, {\"name\": \"Resolver.LookupPort\"}, {\"name\": \"Resolver.LookupSRV\"}, {\"name\": \"Resolver.LookupTXT\"}]}], \"references\": [{\"url\": \"https://go.dev/issue/79006\"}, {\"url\": \"https://groups.google.com/g/golang-announce/c/qcCIEXso47M\"}, {\"url\": \"https://go.dev/cl/775320\"}, {\"url\": \"https://pkg.go.dev/vuln/GO-2026-4971\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"The Dial and LookupPort functions panic on Windows when provided with an input containing a NUL (0).\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"description\": \"CWE-248: Uncaught Exception\"}]}], \"providerMetadata\": {\"orgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"shortName\": \"Go\", \"dateUpdated\": \"2026-05-07T19:41:18.300Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-39836\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-08T21:30:15.127Z\", \"dateReserved\": \"2026-04-07T18:13:03.529Z\", \"assignerOrgId\": \"1bb62c36-49e3-4200-9d77-64a1400537cc\", \"datePublished\": \"2026-05-07T19:41:18.300Z\", \"assignerShortName\": \"Go\"}",
      "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.