CVE-2026-39835 (GCVE-0-2026-39835)
Vulnerability from cvelistv5
Published
2026-05-22 02:31
Modified
2026-05-22 17:45
Severity ?
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE
Summary
SSH servers which use CertChecker as a public key callback without setting IsUserAuthority or IsHostAuthority could be caused to panic by a client presenting a certificate. CertChecker now returns an error instead of panicking when these callbacks are nil.
References
Impacted products
Vendor Product Version
golang.org/x/crypto golang.org/x/crypto/ssh Version: 0   ≤
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        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "LOW",
              "baseScore": 5.3,
              "baseSeverity": "MEDIUM",
              "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:L",
              "version": "3.1"
            }
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          {
            "other": {
              "content": {
                "id": "CVE-2026-39835",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-22T17:44:50.320380Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
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          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-22T17:45:10.853Z",
          "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": "CertChecker.CheckHostKey"
            },
            {
              "name": "CertChecker.Authenticate"
            }
          ],
          "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": "SSH servers which use CertChecker as a public key callback without setting IsUserAuthority or IsHostAuthority could be caused to panic by a client presenting a certificate. CertChecker now returns an error instead of panicking when these callbacks are nil."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-476: NULL Pointer Dereference",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-22T02:31:26.982Z",
        "orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
        "shortName": "Go"
      },
      "references": [
        {
          "url": "https://go.dev/issue/79563"
        },
        {
          "url": "https://groups.google.com/g/golang-announce/c/a082jnz-LvI"
        },
        {
          "url": "https://go.dev/cl/781660"
        },
        {
          "url": "https://pkg.go.dev/vuln/GO-2026-5015"
        }
      ],
      "title": "Invoking  server panic during CheckHostKey/Authenticate in golang.org/x/crypto/ssh"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
    "assignerShortName": "Go",
    "cveId": "CVE-2026-39835",
    "datePublished": "2026-05-22T02:31:26.982Z",
    "dateReserved": "2026-04-07T18:13:03.529Z",
    "dateUpdated": "2026-05-22T17:45:10.853Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
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