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Fencer Intel
medium 5.4

CVE-2021-35478 json

Nagios Log Server before 2.1.9 contains Reflected XSS in the dropdown box for the alert history and audit log function.

published 5y ago modified 4mo ago also EUVD-2021-22120

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
76.6%
EPSS 76.6% chance of exploitation in 30 days, percentile 99.5%
public exploits
0
none known

Summary

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.

Patch / fix

  • nagios log_server 2.1.9

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Exploit prediction

76.62% chance of exploitation in the next 30 days, higher than 99.5% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • research.nccgroup.com https://research.nccgroup.com/2021/07/22/technical-advisory-stored-and-reflected-xss-vulnerability-in-nagios-log-server-cve-2021-35478cve-2021-35479/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.