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.
CVE-2026-57236
HIGHNVD 8.28.2—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 8.2 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 75% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, nvd
8.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.2Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.2
- EG Score
- 8.2(medium)
- EPSS
- 25.1%
- KEV
- Not listed
Published
June 25, 2026
Last Modified
June 26, 2026
Advisory Details (1)
Auto-updated Jun 26, 2026Patch available. Sources: github.
github Patch Available
Possible Use-After-Free when `Nokogiri::XML::Document#encoding=` raises an exception · Advisory · sparklemotion/nokogiri · GitHub
https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-5v8h-3h3q-446pVendor Advisories for CVE-2026-57236(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Frequently asked(5)
What is CVE-2026-57236?
CVE-2026-57236 is a high vulnerability published on June 25, 2026. 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…
When was CVE-2026-57236 disclosed?
CVE-2026-57236 was first published in the National Vulnerability Database on June 25, 2026, with the most recent update on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-57236 actively exploited?
CVE-2026-57236 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 25.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-57236?
CVE-2026-57236 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-57236?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-57236, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-57236
Is Your Infrastructure Affected by CVE-2026-57236?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.