CVE-2026-39830: Golang.org/x/crypto Invoking Client Can Cause Server Vulnerability

CRITICAL
Advisory Identifier: GHSA-vgwf-h737-ff37
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CVSS 9.1
CWE-772 CWE-119
Published
Advisory Summary

CVE-2026-39830 is a CRITICAL (CVSS 9.1) invoking client can cause server vulnerability (CWE-772: Missing Release of Resource after Effective Lifetime) affecting Golang.org/x/crypto libraries in the Go ecosystem. The issue involves invoking client can cause server deadlock on unexpected responses. Remediation is available by upgrading affected packages to version 0.52.0.

CVE-2026-39830 at a Glance

CVE Identifier CVE-2026-39830
GHSA Identifier GHSA-vgwf-h737-ff37
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-772: Missing Release of Resource after Effective Lifetime
Affected Product Golang.org/x/crypto
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 9.1

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:H/I:N/A:H).

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 High (C:H)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-39830

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-2026-39830, 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-772: Missing Release of Resource after Effective Lifetime, where the product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed. 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

A malicious SSH peer could send unsolicited global request responses to fill an internal buffer, blocking the connection's read loop. The blocked goroutine could not be released by calling Close(), resulting in a resource leak per connection. Unsolicited global responses are now discarded.

CVE-2026-39830 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

NVD — CVE-2026-39830 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-39830
access.redhat.com/errata/rhsa-2026:42... WEB
https://access.redhat.com/errata/RHSA-2026:42796
access.redhat.com/errata/rhsa-2026:43... WEB
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-2026:48... WEB
https://access.redhat.com/errata/RHSA-2026:48151
access.redhat.com/errata/rhsa-2026:49... WEB
https://access.redhat.com/errata/RHSA-2026:49944
access.redhat.com/errata/rhsa-2026:51... WEB
https://access.redhat.com/errata/RHSA-2026:51033
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-2026:54400
access.redhat.com/errata/rhsa-2026:54... WEB
https://access.redhat.com/errata/RHSA-2026:54531
access.redhat.com/errata/rhsa-2026:57... WEB
https://access.redhat.com/errata/RHSA-2026:57194
access.redhat.com/errata/rhsa-2026:57... WEB
https://access.redhat.com/errata/RHSA-2026:57801
access.redhat.com/errata/rhsa-2026:59... WEB
https://access.redhat.com/errata/RHSA-2026:59467
access.redhat.com/errata/rhsa-2026:60... WEB
https://access.redhat.com/errata/RHSA-2026:60520
access.redhat.com/errata/rhsa-2026:61... WEB
https://access.redhat.com/errata/RHSA-2026:61314
access.redhat.com/errata/rhsa-2026:65... WEB
https://access.redhat.com/errata/RHSA-2026:65964
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
access.redhat.com/errata/rhsa-2026:67... WEB
https://access.redhat.com/errata/RHSA-2026:67450
Golang.org/x/crypto Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-39830
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2480684
cs.opensource.google/go/x/crypto PACKAGE
https://cs.opensource.google/go/x/crypto
go.dev/cl/781640 WEB
https://go.dev/cl/781640
go.dev/cl/781664 WEB
https://go.dev/cl/781664
go.dev/issue/79564 WEB
https://go.dev/issue/79564
groups.google.com/g/golang-announce/c... WEB
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
pkg.go.dev/vuln/go-2026-5017 WEB
https://pkg.go.dev/vuln/GO-2026-5017
Golang.org/x/crypto Security Information SECURITY
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39830.json
access.redhat.com/errata/rhsa-2026:29... WEB
https://access.redhat.com/errata/RHSA-2026:29455
access.redhat.com/errata/rhsa-2026:35... WEB
https://access.redhat.com/errata/RHSA-2026:35833
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-2026:36... WEB
https://access.redhat.com/errata/RHSA-2026:36808
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-2026:37268
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-2026:37275
access.redhat.com/errata/rhsa-2026:37... WEB
https://access.redhat.com/errata/RHSA-2026:37278
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-2026:40... 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
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

Frequently Asked Questions

What is CVE-2026-39830?
CVE-2026-39830 is a security vulnerability in Golang.org/x/crypto involving Invoking client can cause server deadlock on unexpected responses under CWE-772: Missing Release of Resource after Effective Lifetime.
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-2026-39830?
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-2026-39830?
CVE-2026-39830 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.
What CWE is associated with CVE-2026-39830?
CVE-2026-39830 is classified under CWE-772: Missing Release of Resource after Effective Lifetime (The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.).
How can I check Go dependencies for CVE-2026-39830?
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-vgwf-h737-ff37",
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  "published" : "2026-06-25T22:18:17Z",
  "aliases" : [ "CVE-2026-39830" ],
  "summary" : "golang.org/x/crypto: Invoking client can cause server deadlock on unexpected responses",
  "details" : "A malicious SSH peer could send unsolicited global request responses to fill an internal buffer, blocking the connection's read loop. The blocked goroutine could not be released by calling Close(), resulting in a resource leak per connection. Unsolicited global responses are now discarded.",
  "severity" : [ {
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    "nvd_published_at" : "2026-05-22T04:16:22Z"
  }
}