CVE-2026-39834 (GCVE-0-2026-39834)
Vulnerability from cvelistv5
Published
2026-05-22 02:31
Modified
2026-05-22 18:50
Severity ?
Summary
When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.
Impacted products
Show details on NVD website


{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.1,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "NONE",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-39834",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-22T18:50:30.848292Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-22T18:50:51.339Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "packageName": "golang.org/x/crypto/ssh",
          "product": "golang.org/x/crypto/ssh",
          "programRoutines": [
            {
              "name": "channel.WriteExtended"
            },
            {
              "name": "Dial"
            },
            {
              "name": "NewClientConn"
            },
            {
              "name": "NewServerConn"
            },
            {
              "name": "Session.CombinedOutput"
            },
            {
              "name": "Session.Output"
            },
            {
              "name": "Session.Run"
            },
            {
              "name": "Session.Shell"
            },
            {
              "name": "Session.Start"
            },
            {
              "name": "channel.Write"
            },
            {
              "name": "curve25519sha256.Client"
            },
            {
              "name": "curve25519sha256.Server"
            },
            {
              "name": "dhGEXSHA.Client"
            },
            {
              "name": "dhGEXSHA.Server"
            },
            {
              "name": "dhGroup.Client"
            },
            {
              "name": "dhGroup.Server"
            },
            {
              "name": "ecdh.Client"
            },
            {
              "name": "ecdh.Server"
            },
            {
              "name": "extChannel.Write"
            },
            {
              "name": "mlkem768WithCurve25519sha256.Client"
            },
            {
              "name": "mlkem768WithCurve25519sha256.Server"
            }
          ],
          "vendor": "golang.org/x/crypto",
          "versions": [
            {
              "lessThan": "0.52.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "NCC Group Cryptography Services, sponsored by Teleport"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-190: Integer Overflow or Wraparound",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-22T02:31:27.540Z",
        "orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
        "shortName": "Go"
      },
      "references": [
        {
          "url": "https://go.dev/issue/79567"
        },
        {
          "url": "https://groups.google.com/g/golang-announce/c/a082jnz-LvI"
        },
        {
          "url": "https://go.dev/cl/781663"
        },
        {
          "url": "https://pkg.go.dev/vuln/GO-2026-5020"
        }
      ],
      "title": "Invoking  infinite loop on large channel writes in golang.org/x/crypto/ssh"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
    "assignerShortName": "Go",
    "cveId": "CVE-2026-39834",
    "datePublished": "2026-05-22T02:31:27.540Z",
    "dateReserved": "2026-04-07T18:13:03.529Z",
    "dateUpdated": "2026-05-22T18:50:51.339Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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