9.3Critical
CVE-2026-25896fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names
Description
fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. From 4.1.3to before 5.3.5, a dot (.) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (<, >, &, ", ') with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.
Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.
Affected products and versions
| Vendor | Product | Versions | |
|---|---|---|---|
| advanced cluster security | 4.8 | — | |
| advanced cluster security | 4.9 | — | |
| NaturalIntelligence | fast-xml-parser | >= 5.0.0, < 5.3.5, >= 4.1.3, < 4.5.4 | |
| openshift data foundation | 4.18 | — | |
| openshift data foundation | 4.19 | — | |
| openshift data foundation | 4.20 | — | |
| Red Hat | Migration Toolkit for Applications 8 | all versions | |
| Red Hat | Red Hat Advanced Cluster Security 4.8 | all versions | |
| Red Hat | Red Hat Advanced Cluster Security 4.9 | all versions | |
| Red Hat | Red Hat Developer Hub 1.8 | all versions | |
| Red Hat | Red Hat Developer Hub 1.9 | all versions | |
| Red Hat | Red Hat Openshift Data Foundation 4.18 | all versions | |
| Red Hat | Red Hat Openshift Data Foundation 4.19 | all versions | |
| Red Hat | Red Hat Openshift Data Foundation 4.20 | all versions | |
| Red Hat | Red Hat OpenShift GitOps | all versions | |
| Red Hat | Red Hat OpenShift Virtualization 4 | all versions | |
| Red Hat | Red Hat Satellite 6 | — | |
| Red Hat | Red Hat Satellite 6.18 | all versions | |
| Red Hat | Self-service automation portal 2 | all versions | |
| rhdh | 1.8 | — | |
| rhdh | 1.9 | — | |
| satellite | 6.18 | — |
References and patches
- https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-m7jm-9gc2-mpf2 ExploitMitigationVendor Advisory
- https://github.com/NaturalIntelligence/fast-xml-parser/commit/943ef0eb1b2d3284e72dd74f44a042ee9f07026e Patch
- https://github.com/NaturalIntelligence/fast-xml-parser/commit/ddcd0acf26ddd682cb0dc15a2bd6aa3b96bb1e69 Patch
- https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.5 ProductRelease Notes
- https://access.redhat.com/errata/RHSA-2026:40984
- https://access.redhat.com/errata/RHSA-2026:41941
- https://access.redhat.com/errata/RHSA-2026:41944
- https://access.redhat.com/errata/RHSA-2026:51349
- https://access.redhat.com/errata/RHSA-2026:6174
- https://access.redhat.com/errata/RHSA-2026:6802
- https://access.redhat.com/errata/RHSA-2026:7110
- https://access.redhat.com/errata/RHSA-2026:7128
- https://access.redhat.com/security/cve/CVE-2026-25896
- https://bugzilla.redhat.com/show_bug.cgi?id=2441501
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25896.json
CPE matches (NVD) (1)
cpe:2.3:a:naturalintelligence:fast-xml-parser:*:*:*:*:*:*:*:*≥ 4.1.3 < 5.3.5