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GHSA-6qvp-r6r3-9p7h CVE-2018-14404

Nokogiri NULL Pointer Dereference

High RubyGems
Severity
7.5 / 10
High · CVSS 3.0
Exploit chance (EPSS)
3.75%
Chance of exploitation in the next 30 days. Higher than 89.87% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-476 NULL Pointer Dereference
Fix
1.8.5
Upgrade nokogiri to this version or later

Description

A NULL pointer dereference vulnerability exists in the xpath.c:xmlXPathCompOpEval() function of libxml2 through 2.9.8 when parsing an invalid XPath expression in the XPATH_OP_AND or XPATH_OP_OR case. Applications processing untrusted XSL format inputs with the use of the libxml2 library may be vulnerable to a denial of service attack due to a crash of the application.

Affected versions

RubyGems

PackageVulnerableFixed in
nokogiri
< 1.8.5
1.8.5

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 → 1.8.5

bundler
bundle update nokogiri # Gemfile: gem "nokogiri", ">= 1.8.5"

Severity breakdown

CVSS 3.0 7.5

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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

Weakness

CWE-476: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How to prevent it
  • Implementation: For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished [REF-1484].
  • Requirements: Select a programming language that is not susceptible to these issues.
  • Implementation: Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
  • Architecture and Design: Identify all variables and data stores that receive information from external sources, and apply input validation to make sure that they are only initialized to expected values.
  • Implementation: Explicitly initialize all variables and other data stores, either during declaration or just before the first usage.

References

Advisories

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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