GHSA-78MQ-XCR3-XM33

Vulnerability from github – Published: 2026-06-25 22:15 – Updated: 2026-07-01 15:34
VLAI?
Summary
golang.org/x/crypto/ssh is vulnerable to invoking server panic during CheckHostKey/Authenticate flow
Details

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.

Severity ?
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "golang.org/x/crypto/ssh"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.52.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-39835"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295",
      "CWE-476"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-25T22:15:17Z",
    "nvd_published_at": "2026-05-22T04:16:24Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-78mq-xcr3-xm33",
  "modified": "2026-07-01T15:34:50Z",
  "published": "2026-06-25T22:15:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-39835"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:26546"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:26547"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-39835"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480680"
    },
    {
      "type": "PACKAGE",
      "url": "https://cs.opensource.google/go/x/crypto"
    },
    {
      "type": "WEB",
      "url": "https://go.dev/cl/781660"
    },
    {
      "type": "WEB",
      "url": "https://go.dev/issue/79563"
    },
    {
      "type": "WEB",
      "url": "https://groups.google.com/g/golang-announce/c/a082jnz-LvI"
    },
    {
      "type": "WEB",
      "url": "https://pkg.go.dev/vuln/GO-2026-5015"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39835.json"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "golang.org/x/crypto/ssh is vulnerable to invoking server panic during CheckHostKey/Authenticate flow"
}


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