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GHSA-xh29-r2w5-wx8m CVE-2022-29181

Nokogiri Improperly Handles Unexpected Data Type

High RubyGems
Severity
8.2 / 10
High · CVSS 3.1
Exploit chance (EPSS)
3.23%
Chance of exploitation in the next 30 days. Higher than 88.26% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-241 Improper Handling of Unexpected Data Type
CWE-843 Access of Resource Using Incompatible Type ('Type Confusion')
Fix
1.13.6
Upgrade nokogiri to this version or later

Description

Summary

Nokogiri < v1.13.6 does not type-check all inputs into the XML and HTML4 SAX parsers. For CRuby users, this may allow specially crafted untrusted inputs to cause illegal memory access errors (segfault) or reads from unrelated memory.

Severity

The Nokogiri maintainers have evaluated this as High 8.2 (CVSS3.1).

Mitigation

CRuby users should upgrade to Nokogiri >= 1.13.6.

JRuby users are not affected.

Workarounds

To avoid this vulnerability in affected applications, ensure the untrusted input is a String by calling #to_s or equivalent.

Credit

This vulnerability was responsibly reported by @agustingianni and the Github Security Lab.

Affected versions

RubyGems

PackageVulnerableFixed in
nokogiri
< 1.13.6
1.13.6

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 → 1.13.6

bundler
bundle update nokogiri # Gemfile: gem "nokogiri", ">= 1.13.6"

Severity breakdown

CVSS 3.1 8.2

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

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

Weakness

CWE-241: Improper Handling of Unexpected Data Type

The product does not handle or incorrectly handles when a particular element is not the expected type, e.g. it expects a digit (0-9) but is provided with a letter (A-Z).

How to prevent it
  • Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.

CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')

The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

References

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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