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CVE-2021-47996

7.5 · HIGH

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, inc…

Published Aug 25, 2026CWE-119

Overview

CVE-2021-47996 is a high-severity vulnerability. It was published on August 25, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/GNOME/libxml2/commit/0e1a49c8907645d2e155f0d89d4d9895ac5112b5GitHubgithub.com/GNOME/libxml2/commit/1098c30a040e72a4654968547f415be4e4c40fe7GitHubgithub.com/GNOME/libxml2/commit/1358d157d0bd83be1dfe356a69213df9fac0b539GitHubgithub.com/GNOME/libxml2/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2GitHubgithub.com/GNOME/libxml2/commit/7ffcd44d7e6c46704f8af0321d9314cd26e0e18aGitHubgithub.com/GNOME/libxml2/commit/8598060bacada41a0eb09d95c97744ff4e428f8eGitHubgithub.com/GNOME/libxml2/commit/babe75030c7f64a37826bb3342317134568bef61GitHubgithub.com/GNOME/libxml2/commit/bf22713507fe1fc3a2c4b525cf0a88c2dc87a3a2GitHubgithub.com/sparklemotion/nokogiri/security/advisories/GHSA-7rrm-v45f-jp64Refwww.vulncheck.com/advisories/nokogiri-before-multiple-vulnerabilities-via-libxml2

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47996?

CVE-2021-47996 is a high-severity vulnerability. It was published on August 25, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

How severe is CVE-2021-47996?

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-47996?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47996?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47996 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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