Vulnerability Database

346,508

Total vulnerabilities in the database

Update packaged dependency libxml2 from 2.9.10 to 2.9.12 — nokogiri

Summary

Nokogiri v1.11.4 updates the vendored libxml2 from v2.9.10 to v2.9.12 which addresses:

Note that two additional CVEs were addressed upstream but are not relevant to this release. CVE-2021-3516 via xmllint is not present in Nokogiri, and CVE-2020-7595 has been patched in Nokogiri since v1.10.8 (see #1992).

Please note that this advisory only applies to the CRuby implementation of Nokogiri < 1.11.4, and only if the packaged version of libxml2 is being used. If you've overridden defaults at installation time to use system libraries instead of packaged libraries, you should instead pay attention to your distro's libxml2 release announcements.

Mitigation

Upgrade to Nokogiri >= 1.11.4.

Impact

I've done a brief analysis of the published CVEs that are addressed in this upstream release. The libxml2 maintainers have not released a canonical set of CVEs, and so this list is pieced together from secondary sources and may be incomplete.

All information below is sourced from security.archlinux.org, which appears to have the most up-to-date information as of this analysis.

CVE-2019-20388

  • Severity: Medium
  • Type: Denial of service
  • Description: A memory leak was found in the xmlSchemaValidateStream function of libxml2. Applications that use this library may be vulnerable to memory not being freed leading to a denial of service.
  • Fixed: https://gitlab.gnome.org/GNOME/libxml2/commit/7ffcd44d7e6c46704f8af0321d9314cd26e0e18a

Verified that the fix commit first appears in v2.9.11. It seems possible that this issue would be present in programs using Nokogiri < v1.11.4.

CVE-2020-7595

  • Severity: Medium
  • Type: Denial of service
  • Description: xmlStringLenDecodeEntities in parser.c in libxml2 2.9.10 has an infinite loop in a certain end-of-file situation.
  • Fixed: https://gitlab.gnome.org/GNOME/libxml2/commit/0e1a49c8907645d2e155f0d89d4d9895ac5112b5

This has been patched in Nokogiri since v1.10.8 (see #1992).

CVE-2020-24977

  • Severity: Medium
  • Type: Information disclosure
  • Description: GNOME project libxml2 <= 2.9.10 has a global buffer over-read vulnerability in xmlEncodeEntitiesInternal at libxml2/entities.c.
  • Fixed: https://gitlab.gnome.org/GNOME/libxml2/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2

Verified that the fix commit first appears in v2.9.11. It seems possible that this issue would be present in programs using Nokogiri < v1.11.4.

CVE-2021-3516

  • Severity: Medium
  • Type: Arbitrary code execution (no remote vector)
  • Description: A use-after-free security issue was found libxml2 before version 2.9.11 when "xmllint --html --push" is used to process crafted files.
  • Issue: https://gitlab.gnome.org/GNOME/libxml2/-/issues/230
  • Fixed: https://gitlab.gnome.org/GNOME/libxml2/-/commit/1358d157d0bd83be1dfe356a69213df9fac0b539

Verified that the fix commit first appears in v2.9.11. This vector does not exist within Nokogiri, which does not ship xmllint.

CVE-2021-3517

  • Severity: Medium
  • Type: Arbitrary code execution
  • Description: A heap-based buffer overflow was found in libxml2 before version 2.9.11 when processing truncated UTF-8 input.
  • Issue: https://gitlab.gnome.org/GNOME/libxml2/-/issues/235
  • Fixed: https://gitlab.gnome.org/GNOME/libxml2/-/commit/bf22713507fe1fc3a2c4b525cf0a88c2dc87a3a2

Verified that the fix commit first appears in v2.9.11. It seems possible that this issue would be present in programs using Nokogiri < v1.11.4.

CVE-2021-3518

  • Severity: Medium
  • Type: Arbitrary code execution
  • Description: A use-after-free security issue was found in libxml2 before version 2.9.11 in xmlXIncludeDoProcess() in xinclude.c when processing crafted files.
  • Issue: https://gitlab.gnome.org/GNOME/libxml2/-/issues/237
  • Fixed: https://gitlab.gnome.org/GNOME/libxml2/-/commit/1098c30a040e72a4654968547f415be4e4c40fe7

Verified that the fix commit first appears in v2.9.11. It seems possible that this issue would be present in programs using Nokogiri < v1.11.4.

CVE-2021-3537

  • Severity: Low
  • Type: Denial of service
  • Description: It was found that libxml2 before version 2.9.11 did not propagate errors while parsing XML mixed content, causing a NULL dereference. If an untrusted XML document was parsed in recovery mode and post-validated, the flaw could be used to crash the application.
  • Issue: https://gitlab.gnome.org/GNOME/libxml2/-/issues/243
  • Fixed: https://gitlab.gnome.org/GNOME/libxml2/-/commit/babe75030c7f64a37826bb3342317134568bef61

Verified that the fix commit first appears in v2.9.11. It seems possible that this issue would be present in programs using Nokogiri < v1.11.4.

CVE-2021-3541

  • Severity: Low
  • Type: Denial of service
  • Description: A security issue was found in libxml2 before version 2.9.11. Exponential entity expansion attack its possible bypassing all existing protection mechanisms and leading to denial of service.
  • Fixed: https://gitlab.gnome.org/GNOME/libxml2/-/commit/8598060bacada41a0eb09d95c97744ff4e428f8e

Verified that the fix commit first appears in v2.9.11. It seems possible that this issue would be present in programs using Nokogiri < v1.11.4, however Nokogiri's default parse options prevent the attack from succeeding (it is necessary to opt into DTDLOAD which is off by default).

For more details supporting this analysis of this CVE, please visit #2233.

No technical information available.

No CWE or OWASP classifications available.

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.