CVE-2026-25896 Vulnerability Analysis & Exploit Details

CVE-2026-25896 Vulnerability Summary

CVE-2026-25896: 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.

CVE-2026-25896 References

External References

• https://github.com/NaturalIntelligence/fast-xml-parser/commit/943ef0eb1b2d3284e72dd74f44a042ee9f07026e
• https://github.com/NaturalIntelligence/fast-xml-parser/commit/ddcd0acf26ddd682cb0dc15a2bd6aa3b96bb1e69
• https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.5
• https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-m7jm-9gc2-mpf2

CWE Common Weakness Enumeration

CAPEC Common Attack Pattern Enumeration and Classification

• Command Delimiters CAPEC-15 An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or denylist input validation, as opposed to allowlist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or denylist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on.
• Argument Injection CAPEC-6 An attacker changes the behavior or state of a targeted application through injecting data or command syntax through the targets use of non-validated and non-filtered arguments of exposed services or methods.
• Using Slashes in Alternate Encoding CAPEC-79 This attack targets the encoding of the Slash characters. An adversary would try to exploit common filtering problems related to the use of the slashes characters to gain access to resources on the target host. Directory-driven systems, such as file systems and databases, typically use the slash character to indicate traversal between directories or other container components. For murky historical reasons, PCs (and, as a result, Microsoft OSs) choose to use a backslash, whereas the UNIX world typically makes use of the forward slash. The schizophrenic result is that many MS-based systems are required to understand both forms of the slash. This gives the adversary many opportunities to discover and abuse a number of common filtering problems. The goal of this pattern is to discover server software that only applies filters to one version, but not the other.

Other 5 Recently Published CVEs Vulnerabilities

• CVE-2026-2858 – A vulnerability was identified in wren-lang wren up to 0.4.0. This affects the function peekChar of the file src/vm/wren_compiler.c of the componen...
• CVE-2026-27120 – Leafkit is a templating language with Swift-inspired syntax. Prior to 1.4.1, htmlEscaped in leaf-kit will only escape html special characters if th...
• CVE-2026-27118 – SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Versions of @sveltejs/adapter-vercel prior to 6.3...
• CVE-2026-27113 – Liquid Prompt is an adaptive prompt for Bash and Zsh. Starting in commit cf3441250bb5d8b45f6f8b389fcdf427a99ac28a and prior to commit a4f6b8d8c90b3...
• CVE-2026-27112 – Kargo manages and automates the promotion of software artifacts. From 1.7.0 to before v1.7.8, v1.8.11, and v1.9.3, the batch resource creation endp...