CVE-2023-4979Network attack vector

Authenticated script execution via unescaped outage filters

Published Sep 15, 2023 · Updated Sep 20, 2024

Reflected XSS in LibreNMS before 23.9.0 allows remote authenticated users to run scripts in another user's browser via outage filters. The outages page inserts its to and from filter parameters into inline JavaScript with quote-only escaping instead of neutralizing HTML metacharacters. An attacker needs a LibreNMS account and a victim who opens the crafted outages URL; the script can read browser-accessible data or act as that victim.

CVSS severity5.4
Medium
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in LibreNMS before 23.9.0 allows remote authenticated users to run scripts in another user's browser via outage filters. The outages page inserts its to and from filter parameters into inline JavaScript with quote-only escaping instead of neutralizing HTML metacharacters. An attacker needs a LibreNMS account and a victim who opens the crafted outages URL; the script can read browser-accessible data or act as that victim.

The record

CVE
CVE-2023-4979
Published
Sep 15, 2023
Updated
Sep 20, 2024
Vendor
LibreNMS
Product
LibreNMS
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 20, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <23.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

LibreNMS · LibreNMSversion=unspecified <23.9.0

Published CVSS scores

5.4GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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