Nokogiri updates packaged dependency on libxml2 from 2.9.10 to 2.9.12GHSA-7rrm-v45f-jp64
Fix: sparklemotion/nokogiri@9b90a88GHSA-7rrm-v45f-jp64 is a remote code execution vulnerability in nokogiri. A fix is available for nokogiri — see the affected versions and patch details below.
Real-World Exposure
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Description
Summary
Nokogiri v1.11.4 updates the vendored libxml2 from v2.9.10 to v2.9.12 which addresses:
- CVE-2019-20388 (Medium severity)
- CVE-2020-24977 (Medium severity)
- CVE-2021-3517 (Medium severity)
- CVE-2021-3518 (Medium severity)
- CVE-2021-3537 (Low severity)
- CVE-2021-3541 (Low severity)
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | nokogiri | all versions | 1.11.4bundle update nokogiri --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nokogiri, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update nokogiri to 1.11.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7rrm-v45f-jp64 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Important: Red Hat products utilizing Nokogiri are affected by multiple vulnerabilities in its bundled libxml2 library, which can lead to denial of service, information disclosure, or memory corruption when processing specially crafted XML documents. While Nokogiri's default parse options prevent exponential entity…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for GHSA-7rrm-v45f-jp64 (CC BY 4.0)
Frequently Asked Questions
Is GHSA-7rrm-v45f-jp64 in your dependencies?
Find it across RubyGems, including transitive dependencies.