CVE-2026-39835: Golang.org/x/crypto Golang.org/x/crypto Is Vulnerable To Invoking Vulnerability

MODERATE
Advisory Identifier: GHSA-78mq-xcr3-xm33
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CVSS 5.3
CWE-295 CWE-476
Published
Advisory Summary

CVE-2026-39835 is a MODERATE (CVSS 5.3) golang.org/x/crypto is vulnerable to invoking vulnerability (CWE-295: Improper Certificate Validation) affecting Golang.org/x/crypto libraries in the Go ecosystem. The issue involves golang.org/x/crypto is vulnerable to invoking server panic during checkhostkey/authenticate flow. Remediation is available by upgrading affected packages to version 0.52.0.

CVE-2026-39835 at a Glance

CVE Identifier CVE-2026-39835
GHSA Identifier GHSA-78mq-xcr3-xm33
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-295: Improper Certificate Validation
Affected Product Golang.org/x/crypto
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-39835

To remediate this vulnerability, upgrade all affected Golang.org/x/crypto dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

golang.org/x/crypto fixed: 0.52.0 
Upgrade golang.org/x/crypto to 0.52.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for golang.org/x/crypto

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-39835, inspect your project dependencies for Golang.org/x/crypto:

inspect dependencies for golang.org/x/crypto

Analyze the terminal output to locate any version of Golang.org/x/crypto in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.52.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-295: Improper Certificate Validation, where the product does not validate, or incorrectly validates, a certificate. In Golang.org/x/crypto, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-39835 Affected Golang.org/x/crypto Versions

1 component(s)
Fixed Versions:
0.52.0
Product / Package Ecosystem Affected Versions Fixed Version
golang.org/x/crypto
golang/golang.org/x/crypto
Go
< 0.52.0
0.52.0

References

access.redhat.com/errata/rhsa-2026:41... WEB
https://access.redhat.com/errata/RHSA-2026:41031
access.redhat.com/errata/rhsa-2026:41... WEB
https://access.redhat.com/errata/RHSA-2026:41036
access.redhat.com/errata/rhsa-2026:41... WEB
https://access.redhat.com/errata/RHSA-2026:41066
access.redhat.com/errata/rhsa-2026:42... WEB
https://access.redhat.com/errata/RHSA-2026:42146
NVD — CVE-2026-39835 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-39835
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26546
access.redhat.com/errata/rhsa-2026:42... WEB
https://access.redhat.com/errata/RHSA-2026:42796
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https://access.redhat.com/errata/RHSA-2026:43052
access.redhat.com/errata/rhsa-2026:43... WEB
https://access.redhat.com/errata/RHSA-2026:43692
access.redhat.com/errata/rhsa-2026:46... WEB
https://access.redhat.com/errata/RHSA-2026:46885
access.redhat.com/errata/rhsa-2026:47... WEB
https://access.redhat.com/errata/RHSA-2026:47735
access.redhat.com/errata/rhsa-2026:47... WEB
https://access.redhat.com/errata/RHSA-2026:47949
access.redhat.com/errata/rhsa-2026:48... WEB
https://access.redhat.com/errata/RHSA-2026:48151
access.redhat.com/errata/rhsa-2026:51... WEB
https://access.redhat.com/errata/RHSA-2026:51033
access.redhat.com/errata/rhsa-2026:51... WEB
https://access.redhat.com/errata/RHSA-2026:51036
access.redhat.com/errata/rhsa-2026:51... WEB
https://access.redhat.com/errata/RHSA-2026:51038
access.redhat.com/errata/rhsa-2026:52... WEB
https://access.redhat.com/errata/RHSA-2026:52857
access.redhat.com/errata/rhsa-2026:52... WEB
https://access.redhat.com/errata/RHSA-2026:52910
access.redhat.com/errata/rhsa-2026:54... WEB
https://access.redhat.com/errata/RHSA-2026:54525
access.redhat.com/errata/rhsa-2026:57... WEB
https://access.redhat.com/errata/RHSA-2026:57194
access.redhat.com/errata/rhsa-2026:59... WEB
https://access.redhat.com/errata/RHSA-2026:59467
access.redhat.com/errata/rhsa-2026:59... WEB
https://access.redhat.com/errata/RHSA-2026:59593
access.redhat.com/errata/rhsa-2026:60... WEB
https://access.redhat.com/errata/RHSA-2026:60520
access.redhat.com/errata/rhsa-2026:62... WEB
https://access.redhat.com/errata/RHSA-2026:62260
access.redhat.com/errata/rhsa-2026:65... WEB
https://access.redhat.com/errata/RHSA-2026:65126
access.redhat.com/errata/rhsa-2026:66... WEB
https://access.redhat.com/errata/RHSA-2026:66022
access.redhat.com/errata/rhsa-2026:66... WEB
https://access.redhat.com/errata/RHSA-2026:66521
Golang.org/x/crypto Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-39835
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2480680
cs.opensource.google/go/x/crypto PACKAGE
https://cs.opensource.google/go/x/crypto
go.dev/cl/781660 WEB
https://go.dev/cl/781660
go.dev/issue/79563 WEB
https://go.dev/issue/79563
groups.google.com/g/golang-announce/c... WEB
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
pkg.go.dev/vuln/go-2026-5015 WEB
https://pkg.go.dev/vuln/GO-2026-5015
Golang.org/x/crypto Security Information SECURITY
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39835.json
access.redhat.com/errata/rhsa-2026:26... WEB
https://access.redhat.com/errata/RHSA-2026:26547
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36199
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36207
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36319
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36625
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36648
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36651
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36796
access.redhat.com/errata/rhsa-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36797
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37072
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37123
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37268
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37271
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37272
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37286
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37296
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37387
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37410
access.redhat.com/errata/rhsa-2026:38... WEB
https://access.redhat.com/errata/RHSA-2026:38504
access.redhat.com/errata/rhsa-2026:40... WEB
https://access.redhat.com/errata/RHSA-2026:40118
access.redhat.com/errata/rhsa-2026:40... WEB
https://access.redhat.com/errata/RHSA-2026:40262
access.redhat.com/errata/rhsa-2026:40... WEB
https://access.redhat.com/errata/RHSA-2026:40945
access.redhat.com/errata/rhsa-2026:40... WEB
https://access.redhat.com/errata/RHSA-2026:40969
access.redhat.com/errata/rhsa-2026:40... WEB
https://access.redhat.com/errata/RHSA-2026:40972
access.redhat.com/errata/rhsa-2026:40... WEB
https://access.redhat.com/errata/RHSA-2026:40974
access.redhat.com/errata/rhsa-2026:41... WEB
https://access.redhat.com/errata/RHSA-2026:41019

Frequently Asked Questions

What is CVE-2026-39835?
CVE-2026-39835 is a security vulnerability in Golang.org/x/crypto involving golang.org/x/crypto is vulnerable to invoking server panic during CheckHostKey/Authenticate flow under CWE-295: Improper Certificate Validation.
Which Golang.org/x/crypto versions are affected?
Affected versions include releases prior to 0.52.0 across affected packages: golang.org/x/crypto.
What version fixes CVE-2026-39835?
Upgrading to 0.52.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is golang.org/x/crypto affected?
Yes, golang.org/x/crypto is affected in releases prior to 0.52.0. Upgrade your dependency to 0.52.0 or later.
What is the CVSS score of CVE-2026-39835?
CVE-2026-39835 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2026-39835?
CVE-2026-39835 is classified under CWE-295: Improper Certificate Validation (The product does not validate, or incorrectly validates, a certificate.).
How can I check Go dependencies for CVE-2026-39835?
Run the dependency tree command: 'inspect dependencies for golang.org/x/crypto'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-78mq-xcr3-xm33",
  "modified" : "2026-09-11T15:32:14Z",
  "published" : "2026-06-25T22:15:17Z",
  "aliases" : [ "CVE-2026-39835" ],
  "summary" : "golang.org/x/crypto 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" : [ {
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      "name" : "golang.org/x/crypto"
    },
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  "database_specific" : {
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    "severity" : "MODERATE",
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    "github_reviewed_at" : "2026-06-25T22:15:17Z",
    "nvd_published_at" : "2026-05-22T04:16:24Z"
  }
}