How severe is CVE-2021-35478?

CVE-2021-35478 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-35478 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 77% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-35478?

CVE-2021-35478 affects Nagios Log Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-35478?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-35478 published?

CVE-2021-35478 was published on 2021-07-30 and last updated on 2026-06-17.

CVE-2021-35478

CVE-2021-35478 is a medium-severity vulnerability in Nagios Log Server with a CVSS 3.x base score of 5.4. Its EPSS exploit-prediction score of 77% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 77% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Nagios Log Server
Published: 2021-07-30
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-35478?: 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.
How severe is CVE-2021-35478?: CVE-2021-35478 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-35478 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 77% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-35478?: CVE-2021-35478 affects Nagios Log Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-35478?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-35478 published?: CVE-2021-35478 was published on 2021-07-30 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nagios:log_server:*:*:*:*:*:*:*:*

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