Cyber Resilience

CVE-2021-35478

MediumPublic PoC

Published: 30 July 2021

Published
30 July 2021
Modified
21 November 2024
KEV Added
—
Patch
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CVSS Score v3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EPSS Score 0.4920 97.8th percentile
Risk Priority 40 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-35478 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Nagios Log Server. Its CVSS base score is 5.4 (Medium).

Operationally, ranked in the top 2.2% 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

Nagios Log Server before 2.1.9 contains Reflected XSS in the dropdown box for the alert history and audit log function. All parameters used for filtering are affected. This affects users who open a crafted link or third-party web page.

CWE(s)
CWE-79

Related Threats

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

Affected Assets

nagios
log server
≤ 2.1.9

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-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

SI-10 Information Input Validation
addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

SI-15 Information Output Filtering
addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

References