Cyber Resilience

CVE-2021-3878

CriticalPublic PoC

Published: 15 October 2021

Published
15 October 2021
Modified
08 September 2025
KEV Added
—
Patch
—
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0031 54.9th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-3878 is a critical-severity Improper Restriction of XML External Entity Reference (CWE-611) vulnerability in Stanford Corenlp. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 45.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

corenlp is vulnerable to Improper Restriction of XML External Entity Reference

CWE(s)
CWE-611

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

stanford
corenlp
≤ 4.3.1

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-611

Penetration testing includes XML external entity payloads, detecting XXE vulnerabilities and enabling their mitigation.

SI-4 System Monitoring
addresses: CWE-611

Identifies XML external entity processing via monitoring of unusual file/network access or resource usage.

References