CVE-2021-47996: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-593j-84wv-vpv9
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CVSS 7.5
CWE-119
Published
Advisory Summary

CVE-2021-47996 is a HIGH (CVSS 7.5) security vulnerability vulnerability (CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. this may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.. Remediation is available in the latest vendor maintenance releases.

CVE-2021-47996 at a Glance

CVE Identifier CVE-2021-47996
GHSA Identifier GHSA-593j-84wv-vpv9
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
Affected Product Software
Package Ecosystem Maven
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-2021-47996

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-47996, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer, where the product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. this may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data. In Software, 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

Nokogiri before 1.11.4 (CRuby implementation only, when the packaged/vendored libxml2 is used) bundles libxml2 2.9.10, which is affected by multiple vulnerabilities addressed in libxml2 2.9.12, including a memory leak in xmlSchemaValidateStream (CVE-2019-20388), a global buffer over-read in xmlEncodeEntitiesInternal (CVE-2020-24977), a heap-based buffer overflow (CVE-2021-3517), and an out-of-bounds read (CVE-2021-3518). Processing crafted XML documents may lead to denial of service, information disclosure, or memory corruption.

References

GitHub Advisory / Wiki ADVISORY
https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-7rrm-v45f-jp64
NVD — CVE-2021-47996 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-47996
Security Fix Commit FIX COMMIT
https://github.com/sparklemotion/nokogiri/commit/bf22713507fe1fc3a2c4b525cf0a88c2dc87a3a2
Security Fix Commit FIX COMMIT
https://github.com/sparklemotion/nokogiri/commit/babe75030c7f64a37826bb3342317134568bef61
Security Fix Commit FIX COMMIT
https://github.com/sparklemotion/nokogiri/commit/8598060bacada41a0eb09d95c97744ff4e428f8e
Security Fix Commit FIX COMMIT
https://github.com/sparklemotion/nokogiri/commit/7ffcd44d7e6c46704f8af0321d9314cd26e0e18a
Security Fix Commit FIX COMMIT
https://github.com/sparklemotion/nokogiri/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2
Security Fix Commit FIX COMMIT
https://github.com/sparklemotion/nokogiri/commit/1358d157d0bd83be1dfe356a69213df9fac0b539
Security Fix Commit FIX COMMIT
https://github.com/sparklemotion/nokogiri/commit/1098c30a040e72a4654968547f415be4e4c40fe7
Security Fix Commit FIX COMMIT
https://github.com/sparklemotion/nokogiri/commit/0e1a49c8907645d2e155f0d89d4d9895ac5112b5
Security Fix Commit FIX COMMIT
https://github.com/GNOME/libxml2/commit/bf22713507fe1fc3a2c4b525cf0a88c2dc87a3a2
Security Fix Commit FIX COMMIT
https://github.com/GNOME/libxml2/commit/babe75030c7f64a37826bb3342317134568bef61
Security Fix Commit FIX COMMIT
https://github.com/GNOME/libxml2/commit/8598060bacada41a0eb09d95c97744ff4e428f8e
Security Fix Commit FIX COMMIT
https://github.com/GNOME/libxml2/commit/7ffcd44d7e6c46704f8af0321d9314cd26e0e18a
Security Fix Commit FIX COMMIT
https://github.com/GNOME/libxml2/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2
Security Fix Commit FIX COMMIT
https://github.com/GNOME/libxml2/commit/1358d157d0bd83be1dfe356a69213df9fac0b539
Security Fix Commit FIX COMMIT
https://github.com/GNOME/libxml2/commit/1098c30a040e72a4654968547f415be4e4c40fe7
Security Fix Commit FIX COMMIT
https://github.com/GNOME/libxml2/commit/0e1a49c8907645d2e155f0d89d4d9895ac5112b5
www.vulncheck.com/advisories/nokogiri... WEB
https://www.vulncheck.com/advisories/nokogiri-before-multiple-vulnerabilities-via-libxml2

Frequently Asked Questions

What is CVE-2021-47996?
CVE-2021-47996 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2021-47996?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2021-47996?
CVE-2021-47996 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-2021-47996?
CVE-2021-47996 is classified under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer (The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.).
How can I check Maven dependencies for CVE-2021-47996?
Run the dependency tree command: 'mvn dependency:tree'. 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-593j-84wv-vpv9",
  "modified" : "2026-08-28T18:31:23Z",
  "published" : "2026-08-25T18:31:49Z",
  "aliases" : [ "CVE-2021-47996" ],
  "details" : "Nokogiri before 1.11.4 (CRuby implementation only, when the packaged/vendored libxml2 is used) bundles libxml2 2.9.10, which is affected by multiple vulnerabilities addressed in libxml2 2.9.12, including a memory leak in xmlSchemaValidateStream (CVE-2019-20388), a global buffer over-read in xmlEncodeEntitiesInternal (CVE-2020-24977), a heap-based buffer overflow (CVE-2021-3517), and an out-of-bounds read (CVE-2021-3518). Processing crafted XML documents may lead to denial of service, information disclosure, or memory corruption.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-7rrm-v45f-jp64"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-47996"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/commit/bf22713507fe1fc3a2c4b525cf0a88c2dc87a3a2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/commit/babe75030c7f64a37826bb3342317134568bef61"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/commit/8598060bacada41a0eb09d95c97744ff4e428f8e"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/commit/7ffcd44d7e6c46704f8af0321d9314cd26e0e18a"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/commit/1358d157d0bd83be1dfe356a69213df9fac0b539"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/commit/1098c30a040e72a4654968547f415be4e4c40fe7"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sparklemotion/nokogiri/commit/0e1a49c8907645d2e155f0d89d4d9895ac5112b5"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/GNOME/libxml2/commit/bf22713507fe1fc3a2c4b525cf0a88c2dc87a3a2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/GNOME/libxml2/commit/babe75030c7f64a37826bb3342317134568bef61"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/GNOME/libxml2/commit/8598060bacada41a0eb09d95c97744ff4e428f8e"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/GNOME/libxml2/commit/7ffcd44d7e6c46704f8af0321d9314cd26e0e18a"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/GNOME/libxml2/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/GNOME/libxml2/commit/1358d157d0bd83be1dfe356a69213df9fac0b539"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/GNOME/libxml2/commit/1098c30a040e72a4654968547f415be4e4c40fe7"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/GNOME/libxml2/commit/0e1a49c8907645d2e155f0d89d4d9895ac5112b5"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/nokogiri-before-multiple-vulnerabilities-via-libxml2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-119" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-25T16:16:42Z"
  }
}