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CVE Record

CVE-2021-35478: Nagios Log Server before 2.1.9 contains Reflected XSS in the dropdown box for the alert history and audit l...

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Nagios Log Server before 2.1.9 has a reflected cross-site scripting issue in alert history and audit log filtering. An attacker would need a user to open a crafted link or third-party page. Business risk depends on who uses the console and what their session can access.

Executive priority

Treat this as a targeted administrative-console risk, not an internet worm scenario based on the supplied evidence. Prioritize upgrade or access restriction for any pre-2.1.9 deployment used by privileged staff.

Technical view

CVE-2021-35478 affects filtering parameters used by the alert history and audit log dropdown functionality in Nagios Log Server before 2.1.9. The provided sources describe reflected XSS across all filtering parameters. No CVSS score, CWE, CPE, or confirmed exploitation evidence is included.

Likely exposure

Organizations running Nagios Log Server versions earlier than 2.1.9 are potentially exposed, especially where administrators access the console through normal browsers and can be induced to follow external links.

Exploitation context

The source bundle says exploitation requires a user to open a crafted link or third-party web page. It does not cite CISA KEV listing, active exploitation, public exploit use, or exploitation at scale.

Researcher notes

Evidence is clear on reflected XSS location and affected version range, but incomplete on severity scoring, CWE mapping, CPEs, and exploit activity. Validate exposure through version inventory and route access review rather than assuming broader Nagios product impact.

Mitigation direction

  • Identify all Nagios Log Server deployments and their versions.
  • Upgrade affected systems to version 2.1.9 or later after reviewing Nagios guidance.
  • Limit administrative console access to trusted networks or VPN paths.
  • Warn administrators not to open untrusted links while authenticated.
  • Review NCC Group and Nagios advisories for any additional vendor instructions.

Validation and detection

  • Confirm each Nagios Log Server instance is version 2.1.9 or later.
  • Check whether alert history and audit log pages are reachable by privileged users only.
  • Review logs for unusual requests involving alert history or audit log filters.
  • Verify browser-side security controls and session handling align with internal standards.
  • Document any compensating access controls for systems awaiting upgrade.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2021-35478 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.