CVE Explorer
CVE-2026-33349
fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. From version 4.0.0-beta.3 to before version 5.5.7, the DocTypeReader in fast-xml-parser uses JavaScript truthy checks to evaluate maxEntityCount and maxEntitySize configuration limits. When a developer explicitly sets either limit to 0 — intending to disallow all entities or restrict entity size to zero bytes — the falsy nature of 0 in JavaScript causes the guard conditions to short-circuit, co
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"product":"fast-xml-parser","vendor":"NaturalIntelligence","versions":[{"status":"affected","version":">= 4.0.0-beta.3, < 5.5.7"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:5121df2e8db6c8a371a6ef300cdb19c49b08b589bcdcd0aa4118f1f1162a3f65 · sha256:14890c5b9a6c7617… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":5.9,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:5121df2e8db6c8a371a6ef300cdb19c49b08b589bcdcd0aa4118f1f1162a3f65 · sha256:14890c5b9a6c7617… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-1284","description":"CWE-1284: Improper Validation of Specified Quantity in Input","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:5121df2e8db6c8a371a6ef300cdb19c49b08b589bcdcd0aa4118f1f1162a3f65 · sha256:14890c5b9a6c7617… · /containers/cna/problemTypes/0/descriptions/0
Source references
3 source assertions{"name":"https://github.com/NaturalIntelligence/fast-xml-parser/commit/239b64aa1fc5c5455ddebbbb54a187eb68c9fdb7","tags":["x_refsource_MISC"],"url":"https://github.com/NaturalIntelligence/fast-xml-parser/commit/239b64aa1fc5c5455ddebbbb54a187eb68c9fdb7"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:5121df2e8db6c8a371a6ef300cdb19c49b08b589bcdcd0aa4118f1f1162a3f65 · sha256:14890c5b9a6c7617… · /containers/cna/references/1
{"tags":["exploit"],"url":"https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-jp2q-39xq-3w4g"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:5121df2e8db6c8a371a6ef300cdb19c49b08b589bcdcd0aa4118f1f1162a3f65 · sha256:14890c5b9a6c7617… · /containers/adp/0/references/0
{"name":"https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-jp2q-39xq-3w4g","tags":["x_refsource_CONFIRM"],"url":"https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-jp2q-39xq-3w4g"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:5121df2e8db6c8a371a6ef300cdb19c49b08b589bcdcd0aa4118f1f1162a3f65 · sha256:14890c5b9a6c7617… · /containers/cna/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.