Incorrect Regular Expression Affecting fast-xml-parser package, versions >=4.1.3 <4.5.4>=5.0.0 <5.3.5
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-JS-FASTXMLPARSER-15324289
- published20 Feb 2026
- disclosed20 Feb 2026
- creditochko
Introduced: 20 Feb 2026
NewCVE-2026-25896 (opens in a new tab)How to fix?
Upgrade fast-xml-parser to version 4.5.4, 5.3.5 or higher.
Overview
fast-xml-parser is a Validate XML, Parse XML, Build XML without C/C++ based libraries
Affected versions of this package are vulnerable to Incorrect Regular Expression in the entity parsing RegEx in DOCTYPE declarations. An attacker can inject arbitrary values that override built-in XML entities by crafting entity names containing ., which is interpreted as a regex wildcard, allowing malicious content to be substituted in place of standard entities when the XML is parsed and subsequently rendered or used in sensitive contexts.