CVE-2025-47911: Golang.org/x/net/html Golang.org/x/net/html Has A Quadratic Parsing Vulnerability

MODERATE
Advisory Identifier: GHSA-w4gw-w5jq-g9jh
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CVSS 5.3
CWE-407
Published
Advisory Summary

CVE-2025-47911 is a MODERATE (CVSS 5.3) golang.org/x/net/html has a quadratic parsing vulnerability (CWE-407: Inefficient Algorithmic Complexity) affecting Golang.org/x/net/html libraries in the Go ecosystem. The issue involves golang.org/x/net/html has a quadratic parsing complexity issue. Remediation is available by upgrading affected packages to version 0.45.0.

CVE-2025-47911 at a Glance

CVE Identifier CVE-2025-47911
GHSA Identifier GHSA-w4gw-w5jq-g9jh
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-407: Inefficient Algorithmic Complexity
Affected Product Golang.org/x/net/html
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-2025-47911

To remediate this vulnerability, upgrade all affected Golang.org/x/net/html 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/html fixed: 0.45.0 
Upgrade golang.org/x/net/html to 0.45.0
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/html

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-47911, inspect your project dependencies for Golang.org/x/net/html:

inspect dependencies for golang.org/x/net/html

Analyze the terminal output to locate any version of Golang.org/x/net/html in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.45.0), 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-407: Inefficient Algorithmic Complexity, where an algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. In Golang.org/x/net/html, 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

The html.Parse function in golang.org/x/net/html has quadratic parsing complexity when processing certain inputs, which can lead to Denial of Service (DoS) if an attacker provides specially crafted HTML content.

CVE-2025-47911 Affected Golang.org/x/net/html Versions

1 component(s)
Fixed Versions:
0.45.0
Product / Package Ecosystem Affected Versions Fixed Version
golang.org/x/net/html
golang/golang.org/x/net/html
Go
< 0.45.0
0.45.0

References

NVD — CVE-2025-47911 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-47911
Golang.org/x/net/html Source Repository REPOSITORY
https://github.com/golang/vulndb/issues/4440
go.dev/cl/709876 WEB
https://go.dev/cl/709876
go.googlesource.com/net PACKAGE
https://go.googlesource.com/net
groups.google.com/g/golang-announce/c... WEB
https://groups.google.com/g/golang-announce/c/jnQcOYpiR2c
pkg.go.dev/vuln/go-2026-4440 WEB
https://pkg.go.dev/vuln/GO-2026-4440

Frequently Asked Questions

What is CVE-2025-47911?
CVE-2025-47911 is a security vulnerability in Golang.org/x/net/html involving golang.org/x/net/html has a Quadratic Parsing Complexity issue under CWE-407: Inefficient Algorithmic Complexity.
Which Golang.org/x/net/html versions are affected?
Affected versions include releases prior to 0.45.0 across affected packages: golang.org/x/net/html.
What version fixes CVE-2025-47911?
Upgrading to 0.45.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is golang.org/x/net/html affected?
Yes, golang.org/x/net/html is affected in releases prior to 0.45.0. Upgrade your dependency to 0.45.0 or later.
What is the CVSS score of CVE-2025-47911?
CVE-2025-47911 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-2025-47911?
CVE-2025-47911 is classified under CWE-407: Inefficient Algorithmic Complexity (An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.).
How can I check Go dependencies for CVE-2025-47911?
Run the dependency tree command: 'inspect dependencies for golang.org/x/net/html'. 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-w4gw-w5jq-g9jh",
  "modified" : "2026-02-12T22:06:13Z",
  "published" : "2026-02-12T22:06:13Z",
  "aliases" : [ "CVE-2025-47911" ],
  "summary" : "golang.org/x/net/html has a Quadratic Parsing Complexity issue",
  "details" : "The html.Parse function in golang.org/x/net/html has quadratic parsing complexity when processing certain inputs, which can lead to Denial of Service (DoS) if an attacker provides specially crafted HTML content.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "golang.org/x/net/html"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.45.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-47911"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/golang/vulndb/issues/4440"
  }, {
    "type" : "WEB",
    "url" : "https://go.dev/cl/709876"
  }, {
    "type" : "PACKAGE",
    "url" : "https://go.googlesource.com/net"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/g/golang-announce/c/jnQcOYpiR2c"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/vuln/GO-2026-4440"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-407" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-12T22:06:13Z",
    "nvd_published_at" : "2026-02-05T18:16:09Z"
  }
}