CVE-2026-39834: Golang.org/x/crypto Golang.org/x/crypto Vulnerable To Infinite Loop Vulnerability

CRITICAL
Advisory Identifier: GHSA-rm3j-f69w-wqmq
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CVSS 9.1
CWE-190
Published
Advisory Summary

CVE-2026-39834 is a CRITICAL (CVSS 9.1) golang.org/x/crypto vulnerable to infinite loop vulnerability (CWE-190: Integer Overflow or Wraparound) affecting Golang.org/x/crypto libraries in the Go ecosystem. The issue involves golang.org/x/crypto vulnerable to infinite loop on large channel writes. Remediation is available by upgrading affected packages to version 0.52.0.

CVE-2026-39834 at a Glance

CVE Identifier CVE-2026-39834
GHSA Identifier GHSA-rm3j-f69w-wqmq
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-190: Integer Overflow or Wraparound
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:N/I:H/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 None (C:N)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-39834

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-2026-39834, 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-190: Integer Overflow or Wraparound, where the product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. this occurs when an integer value is incremented to a value that is too large to store in the associated representation. when this occurs, the value may become a very small or negative number. 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

When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.

CVE-2026-39834 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-2026-39834 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-39834
cs.opensource.google/go/x/crypto PACKAGE
https://cs.opensource.google/go/x/crypto
go.dev/cl/781663 WEB
https://go.dev/cl/781663
go.dev/issue/79567 WEB
https://go.dev/issue/79567
groups.google.com/g/golang-announce/c... WEB
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
pkg.go.dev/vuln/go-2026-5020 WEB
https://pkg.go.dev/vuln/GO-2026-5020

Frequently Asked Questions

What is CVE-2026-39834?
CVE-2026-39834 is a security vulnerability in Golang.org/x/crypto involving golang.org/x/crypto vulnerable to infinite loop on large channel writes under CWE-190: Integer Overflow or Wraparound.
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-2026-39834?
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-2026-39834?
CVE-2026-39834 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:N/I:H/A:H.
What CWE is associated with CVE-2026-39834?
CVE-2026-39834 is classified under CWE-190: Integer Overflow or Wraparound (The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.).
How can I check Go dependencies for CVE-2026-39834?
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-rm3j-f69w-wqmq",
  "modified" : "2026-07-07T15:26:18Z",
  "published" : "2026-06-25T22:21:40Z",
  "aliases" : [ "CVE-2026-39834" ],
  "summary" : "golang.org/x/crypto vulnerable to infinite loop on large channel writes",
  "details" : "When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "golang.org/x/crypto"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.52.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-39834"
  }, {
    "type" : "PACKAGE",
    "url" : "https://cs.opensource.google/go/x/crypto"
  }, {
    "type" : "WEB",
    "url" : "https://go.dev/cl/781663"
  }, {
    "type" : "WEB",
    "url" : "https://go.dev/issue/79567"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/g/golang-announce/c/a082jnz-LvI"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/vuln/GO-2026-5020"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-190" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-25T22:21:40Z",
    "nvd_published_at" : "2026-05-22T04:16:24Z"
  }
}