---
id: CVE-2026-39835
title: >-
  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
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…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-295
  - CWE-476
vendor: golang
product: crypto
affected:
  - crypto < 0.52.0
patched:
  - crypto 0.52.0
published: '2026-05-22'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T13:18:12.740'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-39835'
references:
  - url: 'https://go.dev/cl/781660'
    label: security@golang.org
  - url: 'https://go.dev/issue/79563'
    label: security@golang.org
  - url: 'https://groups.google.com/g/golang-announce/c/a082jnz-LvI'
    label: security@golang.org
  - url: 'https://pkg.go.dev/vuln/GO-2026-5015'
    label: security@golang.org
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  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-39835'
  - url: 'https://cs.opensource.google/go/x/crypto'
  - url: 'https://github.com/advisories/GHSA-78mq-xcr3-xm33'
tags:
  - nvd
  - cve.org
  - osv
  - go
  - ghsa
epss: 0.00662
epssPercentile: 0.49454
aliases:
  - GHSA-78mq-xcr3-xm33
  - GO-2026-5015
ecosystem: go
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-05-22T17:44:50.320380Z'
ingestedAt: '2026-06-26T16:43:14.197Z'
---

## Overview

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.

## Affected

- `crypto < 0.52.0`

## Remediation

Upgrade past the affected range:

- `crypto 0.52.0`

## Package advisory (CVE-2026-39835)

Affected packages:

- `golang.org/x/crypto < 0.52.0`

Patched in:

- `golang.org/x/crypto 0.52.0`

Source: https://osv.dev/vulnerability/GHSA-78mq-xcr3-xm33