GHSA-9cv2-cfxc-v4v2 CVE-2026-57434
Nokogiri: Null Pointer Dereference calling methods on uninitialized wrapper classes
- Severity
- 0.0 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.46%
- Chance of exploitation in the next 30 days. Higher than 39.89% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-476 NULL Pointer Dereference
- Fix
1.19.4- Upgrade nokogiri to this version or later
Description
Summary
Nokogiri contains a bug when calling certain methods on allocated-but-uninitialized native wrapper classes that inherit from Nokogiri::XML::Node. This caused a NULL pointer dereference that could crash the process.
Nokogiri 1.19.4 checks for missing native data pointers and raises a RuntimeError.
JRuby is not affected.
Severity
The Nokogiri maintainers have evaluated this as low severity. This is only triggered by a programming error. It requires application code to call .allocate directly on a native-backed class and then invoke methods on the resulting uninitialized object. It cannot be triggered by untrusted input or through normal use of the public API.
Mitigation
Upgrade to Nokogiri 1.19.4 or later.
Avoid calling .allocate directly on Nokogiri native-backed classes. Use the documented constructors and factory methods instead.
Credit
This issue was responsibly reported by Zheng Yu from depthfirst.com.
Affected versions
RubyGems
| Package | Vulnerable | Fixed in |
|---|---|---|
| nokogiri | < 1.19.4 |
1.19.4 |
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 → 1.19.4
- bundler
bundle update nokogiri # Gemfile: gem "nokogiri", ">= 1.19.4"
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- Low
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
- Exploit maturity
- Unreported
CVSS 3.1 7.5
CVSS:3.1/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
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why 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-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 |
| GHSA-v2fc-qm4h-8hqv Nokogiri XSLT transform has a memory leak | Medium | Also affects nokogiri |
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