Nokogiri: Possible Use-After-Free when setting an attribute value via Nokogiri::XML::Attr#value= or #content=

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

1.7 · 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 · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary Nokogiri’s CRuby native extension could leave a Ruby wrapper pointing to freed memory when replacing the value of an XML attribute. If Ruby code had already accessed an attribute child node, Nokogiri::XML::Attr#value= could free the underlying native child node while the wrapper remained reachable through the document node cache. A later use of the freed child node or a Ruby GC mark could dereference an invalid pointer, causing an invalid read and a possible segfault. Nokogiri 1.19.4 preserves any already-wrapped attribute child nodes before replacing the attribute value. 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 directly access an attribute's child node and then replace that same attribute's value via Attr#value= or #content=. Nokogiri 1.19.4 makes this pattern safe with no change to the public API. Already-wrapped…

Published by the source

19 Jun 2026, 16:37 UTC

Last modified by the source

19 Jun 2026, 16:37 UTC

Source last checked

26 Oct 2026, 15:52 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-phwj-rprq-35pp

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-phwj-rprq-35pp

Advisory: Nokogiri: Possible Use-After-Free when setting an attribute value via `Nokogiri::XML::Attr#value=` or `#content=`
IDs: GHSA-phwj-rprq-35pp
Record: https://patchnext.com/advisories/ghsa-phwj-rprq-35pp (revision 1, source checked 26 Oct 2026, 15:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 1.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: nokogiri 1.19.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems nokogiri: affected < 1.19.4; fixed in 1.19.4

## Suggested inspection (read-only)
- RubyGems nokogiri: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on nokogiri.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-phwj-rprq-35pp (GitHub-reviewed advisory GHSA-phwj-rprq-35pp lists affected ranges: RubyGems nokogiri >=0 <1.19.4)

Commands are suggestions: review each one before running it.