GHSA-wfpw-mmfh-qq69 CVE-2026-57438
Nokogiri: Possible Use-After-Free in XInclude Processing
- Severity
- 2.2 / 10
- Low · CVSS 4.0
- Exploit chance (EPSS)
- 0.12%
- Chance of exploitation in the next 30 days. Higher than 2.16% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-416 Use After Free
- Fix
1.19.4- Upgrade nokogiri to this version or later
Description
Summary
XInclude substitution performed by Nokogiri::XML::Node#do_xinclude replaced each <xi:include> in place, freeing the include node along with its children (such as <xi:fallback> and its descendants) and any namespaces declared on them. If an application had already exposed one of those nodes or namespaces to Ruby, the corresponding Ruby object was left pointing at freed memory. Using the object could result in invalid reads or writes to memory.
Nokogiri 1.19.4 substitutes each <xi:include> on a defensive copy by default, so the structures libxml2 frees are never the ones bound to live Ruby objects.
Only the CRuby implementation is affected; JRuby is not affected.
Severity
The Nokogiri maintainers have evaluated this as low severity. Reaching it requires an unusual API-usage pattern that does not arise during normal use. The application must parse a document without XInclude, traverse into an <xi:include> subtree to expose its nodes or namespaces to Ruby, and only then invoke XInclude processing. The common case, requesting XInclude at parse time, operates on a freshly parsed document whose nodes are not yet exposed to Ruby and is not affected. Nokogiri 1.19.4 makes this pattern safe by default and requires no change to application code.
Mitigation
Upgrade to Nokogiri 1.19.4 or later.
As a workaround for earlier versions, perform XInclude substitution at parse time (with the xinclude parse option) rather than calling #do_xinclude on a document that has already been traversed. A freshly parsed document has no nodes exposed to Ruby, so the substitution is safe.
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 2.2
CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Attack vector
- Local
- Attack complexity
- High
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
- Exploit maturity
- Unreported
- Scope
- X
CVSS 3.1 6.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- 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
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-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 |
| GHSA-v2fc-qm4h-8hqv Nokogiri XSLT transform has a memory leak | Medium | Also affects nokogiri |
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