CVE-2021-38561: Golang.org/x/text Golang.org/x/text/language Out-of-bounds Read Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-ppp9-7jff-5vj2
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CVSS 7.5
CWE-125
Published
Advisory Summary

CVE-2021-38561 is a HIGH (CVSS 7.5) golang.org/x/text/language out-of-bounds read vulnerability vulnerability (CWE-125: Out-of-bounds Read) affecting Golang.org/x/text libraries in the Go ecosystem. The issue involves golang.org/x/text/language out-of-bounds read vulnerability. Remediation is available by upgrading affected packages to version 0.3.7.

CVE-2021-38561 at a Glance

CVE Identifier CVE-2021-38561
GHSA Identifier GHSA-ppp9-7jff-5vj2
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-125: Out-of-bounds Read
Affected Product Golang.org/x/text
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 7.5

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:N/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 None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2021-38561

To remediate this vulnerability, upgrade all affected Golang.org/x/text 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/text fixed: 0.3.7 
Upgrade golang.org/x/text to 0.3.7
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/text

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-38561, inspect your project dependencies for Golang.org/x/text:

inspect dependencies for golang.org/x/text

Analyze the terminal output to locate any version of Golang.org/x/text in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.3.7), 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-125: Out-of-bounds Read, where the product reads data past the end, or before the beginning, of the intended buffer. In Golang.org/x/text, 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

golang.org/x/text/language in golang.org/x/text before 0.3.7 can panic with an out-of-bounds read during BCP 47 language tag parsing. Index calculation is mishandled. If parsing untrusted user input, this can be used as a vector for a denial-of-service attack.

CVE-2021-38561 Affected Golang.org/x/text Versions

1 component(s)
Fixed Versions:
0.3.7
Product / Package Ecosystem Affected Versions Fixed Version
golang.org/x/text
golang/golang.org/x/text
Go
< 0.3.7
0.3.7

References

NVD — CVE-2021-38561 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-38561
deps.dev/advisory/osv/go-202... WEB
https://deps.dev/advisory/OSV/GO-2021-0113
go.dev/cl/340830 WEB
https://go.dev/cl/340830
go.googlesource.com/text/+/383b2e75a7a4... WEB
https://go.googlesource.com/text/+/383b2e75a7a4198c42f8f87833eefb772868a56f
groups.google.com/g/golang-announce WEB
https://groups.google.com/g/golang-announce
pkg.go.dev/golang.org/x/text/l... WEB
https://pkg.go.dev/golang.org/x/text/language
pkg.go.dev/vuln/go-2021-0113 WEB
https://pkg.go.dev/vuln/GO-2021-0113

Frequently Asked Questions

What is CVE-2021-38561?
CVE-2021-38561 is a security vulnerability in Golang.org/x/text involving golang.org/x/text/language Out-of-bounds Read vulnerability under CWE-125: Out-of-bounds Read.
Which Golang.org/x/text versions are affected?
Affected versions include releases prior to 0.3.7 across affected packages: golang.org/x/text.
What version fixes CVE-2021-38561?
Upgrading to 0.3.7 (or the latest patched release for your respective branch) resolves the vulnerability.
Is golang.org/x/text affected?
Yes, golang.org/x/text is affected in releases prior to 0.3.7. Upgrade your dependency to 0.3.7 or later.
What is the CVSS score of CVE-2021-38561?
CVE-2021-38561 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-38561?
CVE-2021-38561 is classified under CWE-125: Out-of-bounds Read (The product reads data past the end, or before the beginning, of the intended buffer.).
How can I check Go dependencies for CVE-2021-38561?
Run the dependency tree command: 'inspect dependencies for golang.org/x/text'. 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-ppp9-7jff-5vj2",
  "modified" : "2025-04-14T22:09:42Z",
  "published" : "2022-12-26T06:30:22Z",
  "aliases" : [ "CVE-2021-38561" ],
  "summary" : "golang.org/x/text/language Out-of-bounds Read vulnerability",
  "details" : "golang.org/x/text/language in golang.org/x/text before 0.3.7 can panic with an out-of-bounds read during BCP 47 language tag parsing. Index calculation is mishandled. If parsing untrusted user input, this can be used as a vector for a denial-of-service attack.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "golang.org/x/text"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.3.7"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-38561"
  }, {
    "type" : "WEB",
    "url" : "https://deps.dev/advisory/OSV/GO-2021-0113"
  }, {
    "type" : "WEB",
    "url" : "https://go.dev/cl/340830"
  }, {
    "type" : "WEB",
    "url" : "https://go.googlesource.com/text/+/383b2e75a7a4198c42f8f87833eefb772868a56f"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/g/golang-announce"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/golang.org/x/text/language"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/vuln/GO-2021-0113"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-125" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-01-09T20:02:12Z",
    "nvd_published_at" : "2022-12-26T06:15:00Z"
  }
}