CVE-2026-33349 impacts the `fast-xml-parser` library (versions 4.0.0-beta.3 to before 5.5.7), where a logic error in the `DocTypeReader` allows entity limit bypass. Specifically, setting `maxEntityCount` or `maxEntitySize` to zero disables these limits due to JavaScript's truthy/falsy evaluation, enabling an attacker to supply malicious XML. This vulnerability, rated MEDIUM (CVSS 5.9) with a network attack vector and high complexity, can lead to denial of service through unbounded entity expansion and memory exhaustion. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
>= 4.0.1, < 4.5.5CPE matchmatch criteria | cpe:2.3:a:naturalintelligence:fast-xml-parser:*:*:*:*:*:*:*:* | ||
>= 5.0.0, < 5.5.7CPE matchmatch criteria | cpe:2.3:a:naturalintelligence:fast-xml-parser:*:*:*:*:*:*:*:* | ||
4.0.0CPE matchmatch criteria | cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:-:*:*:*:*:*:* | ||
4.0.0CPE matchmatch criteria | cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:beta3:*:*:*:*:*:* | ||
4.0.0CPE matchmatch criteria | cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:beta4:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
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