Medium [CVE-2026-57236] Denial of Service or Information Disclosure via invalid encoding handling
This medium-severity Red Hat Linux advisory covers CVE-2026-57236 affecting Red Hat Satellite 6.16 for RHEL 8, Red Hat Satellite 6.16 for RHEL 9, Red Hat Satellite 6.17 for RHEL 9.
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Summary
Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, calling Document#encoding= with an invalid encoding (e.g., a non-string, or a string containing a null byte) raises an exception, but only after freeing the document's current encoding string without replacing it.
The document is left referencing freed memory, so the next call to Document#encoding reads invalid memory, which can cause a segfault or leak freed bytes into a Ruby String. Affects the CRuby (libxml2) implementation only; JRuby is not affected.
This vulnerability is fixed in 1.19.4. This leaves the document referencing freed memory, which can lead to a denial of service (DoS) due to a segmentation fault or information disclosure by leaking freed memory into a Ruby String.
This flaw has an Important impact as Nokogiri's CRuby implementation in Red Hat products is vulnerable to a use-after-free when processing invalid encoding values. Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H).
Weakness: CWE-825. Affected Red Hat products: Red Hat Satellite 6.16 for RHEL 8; Red Hat Satellite 6.16 for RHEL 9; Red Hat Satellite 6.17 for RHEL 9; Red Hat Satellite 6.18 for RHEL 9; Red Hat Satellite 6.19 for RHEL 9; Red Hat Satellite 6.
Red Hat fixing advisory: RHSA-2026:50223, RHSA-2026:50222, RHSA-2026:50263, RHSA-2026:50221.
- < 1.19.4
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
- 1.19.4
- rubygem-nokogiri-0:1.15.7-3.el8sat
- rubygem-nokogiri-0:1.15.7-3.el9sat
- rubygem-nokogiri-0:1.17.2-3.el9sat
- RHSA-2026:50223
- RHSA-2026:50222
- RHSA-2026:50263
- RHSA-2026:50221
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
Mitigation checklist
- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
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