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GHSA-v4f8-2847-rwm7 CVE-2021-3518

Nokogiri Implements libxml2 version vulnerable to use-after-free

High RubyGems
Severity
8.8 / 10
High · CVSS 3.1
Exploit chance (EPSS)
21.86%
Chance of exploitation in the next 30 days. Higher than 97.65% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-416 Use After Free
Fix
1.11.4
Upgrade nokogiri to this version or later

Description

There's a flaw in libxml2 in versions before 2.9.11. An attacker who is able to submit a crafted file to be processed by an application linked with libxml2 could trigger a use-after-free. The greatest impact from this flaw is to confidentiality, integrity, and availability.

Affected versions

RubyGems

PackageVulnerableFixed in
nokogiri
< 1.11.4
1.11.4

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

nokogiri RubyGems → 1.11.4

bundler
bundle update nokogiri # Gemfile: gem "nokogiri", ">= 1.11.4"

Severity breakdown

CVSS 3.1 8.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Weakness

CWE-416: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

How to prevent it
  • Architecture and Design: Choose a language that provides automatic memory management.
  • Implementation: When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

References

Advisories

Packages

Other links

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
GHSA-phwj-rprq-35pp
Nokogiri: Possible Use-After-Free when setting an attribute value via `Nokogiri::XML::Attr#value=` or `#content=`
High Also affects nokogiri
GHSA-wfpw-mmfh-qq69
Nokogiri: Possible Use-After-Free in XInclude Processing
Low Also affects nokogiri
GHSA-p67v-3w7g-wjg7
Nokogiri: Possible Use-After-Free when directly using `NokogirI::XML::XPathContext` beyond document lifetime
Medium Also affects nokogiri
GHSA-wjv4-x9w8-wm3h
Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node type
Medium Also affects nokogiri
GHSA-5prr-v3j2-97mh
Nokogiri: Possible Out-of-Bounds Read in `Nokogiri::XML::NodeSet#[]`
High Also affects nokogiri
GHSA-9cv2-cfxc-v4v2
Nokogiri: Null Pointer Dereference calling methods on uninitialized wrapper classes
High Also affects nokogiri
GHSA-8678-w3jw-xfc2
Nokogiri: XML::Schema on JRuby allows network requests when NONET is set, bypassing CVE-2020-26247
Low Also affects nokogiri
GHSA-5v8h-3h3q-446p
Nokogiri: Possible Use-After-Free when `Nokogiri::XML::Document#encoding=` raises an exception
High Also affects nokogiri
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