CVE-2026-25680: Golang.org/x/net Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-5cv4-jp36-h3mw
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CVSS 6.5
CWE-400
Published
Advisory Summary

CVE-2026-25680 is a MODERATE (CVSS 6.5) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Golang.org/x/net libraries in the Go ecosystem. The issue involves go net html parser is vulnerable to denial of service. Remediation is available by upgrading affected packages to version 0.55.0.

CVE-2026-25680 at a Glance

CVE Identifier CVE-2026-25680
GHSA Identifier GHSA-5cv4-jp36-h3mw
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Golang.org/x/net
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 6.5

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:R/S:U/C:N/I:N/A:H).

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

How to Fix CVE-2026-25680

To remediate this vulnerability, upgrade all affected Golang.org/x/net 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/net fixed: 0.55.0 
Upgrade golang.org/x/net to 0.55.0
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/net

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-25680, inspect your project dependencies for Golang.org/x/net:

inspect dependencies for golang.org/x/net

Analyze the terminal output to locate any version of Golang.org/x/net in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.55.0), 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-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Golang.org/x/net, 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

In Go Net (`golang.org/x/net`) before verion 0.55.0, parsing arbitrary HTML can consume excessive CPU time, possibly leading to denial of service.

CVE-2026-25680 Affected Golang.org/x/net Versions

1 component(s)
Fixed Versions:
0.55.0
Product / Package Ecosystem Affected Versions Fixed Version
golang.org/x/net
golang/golang.org/x/net
Go
< 0.55.0
0.55.0

References

NVD — CVE-2026-25680 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-25680
go.dev/cl/781702 WEB
https://go.dev/cl/781702
go.dev/issue/79573 WEB
https://go.dev/issue/79573
go.googlesource.com/net/+/08be507abce89... WEB
https://go.googlesource.com/net/+/08be507abce89191d78cd49da60f4501fc910472
go.googlesource.com/net/+/refs/tags/v0.... WEB
https://go.googlesource.com/net/+/refs/tags/v0.55.0
groups.google.com/g/golang-announce/c... WEB
https://groups.google.com/g/golang-announce/c/iI-mYSI0lu8
pkg.go.dev/vuln/go-2026-5028 WEB
https://pkg.go.dev/vuln/GO-2026-5028
cs.opensource.google... PACKAGE
cs.opensource.google/go/x/net

Frequently Asked Questions

What is CVE-2026-25680?
CVE-2026-25680 is a security vulnerability in Golang.org/x/net involving Go Net HTML parser is vulnerable to denial of service under CWE-400: Uncontrolled Resource Consumption.
Which Golang.org/x/net versions are affected?
Affected versions include releases prior to 0.55.0 across affected packages: golang.org/x/net.
What version fixes CVE-2026-25680?
Upgrading to 0.55.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is golang.org/x/net affected?
Yes, golang.org/x/net is affected in releases prior to 0.55.0. Upgrade your dependency to 0.55.0 or later.
What is the CVSS score of CVE-2026-25680?
CVE-2026-25680 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-25680?
CVE-2026-25680 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check Go dependencies for CVE-2026-25680?
Run the dependency tree command: 'inspect dependencies for golang.org/x/net'. 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-5cv4-jp36-h3mw",
  "modified" : "2026-07-01T17:58:07Z",
  "published" : "2026-05-26T13:30:17Z",
  "aliases" : [ "CVE-2026-25680" ],
  "summary" : "Go Net HTML parser is vulnerable to denial of service",
  "details" : "In Go Net (`golang.org/x/net`) before verion 0.55.0, parsing arbitrary HTML can consume excessive CPU time, possibly leading to denial of service.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "golang.org/x/net"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.55.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-25680"
  }, {
    "type" : "WEB",
    "url" : "https://go.dev/cl/781702"
  }, {
    "type" : "WEB",
    "url" : "https://go.dev/issue/79573"
  }, {
    "type" : "WEB",
    "url" : "https://go.googlesource.com/net/+/08be507abce89191d78cd49da60f4501fc910472"
  }, {
    "type" : "WEB",
    "url" : "https://go.googlesource.com/net/+/refs/tags/v0.55.0"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/g/golang-announce/c/iI-mYSI0lu8"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/vuln/GO-2026-5028"
  }, {
    "type" : "PACKAGE",
    "url" : "cs.opensource.google/go/x/net"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-01T17:58:07Z",
    "nvd_published_at" : "2026-05-22T16:16:19Z"
  }
}