CVE-2024-13993VulnerabilityPublished 30 Oct 2025Updated 17 Nov 2025

CVE-2024-13993: Nagios XI · XSS or 'Cross-site Scripting'

Affects Nagios XISource CVE Database V5

Not known to be exploited · CVSS 5.1 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

5.1Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.7% chance of exploitation in 30 days – higher than 56% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: Active
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: Low
Subsequent system integrity: Low
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Active: Successful exploitation of this vulnerability requires a targeted user to perform specific, conscious interactions with the vulnerable system and the attacker’s payload, or the user’s interactions would actively subvert protection mechanisms which would lead to exploitation of the vulnerability.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
Subsequent system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Subsequent System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Nagios XI	Affected =0	Fixed in–

AI-suggested

1. Upgrade Nagios XI installations to version 2024R1.1.2 or later, where the vulnerability is patched. 2. Enforce strict browser usage policies that mandate modern, up-to-date browsers with built-in XSS protections for all users accessing Nagios XI, especially administrators. 3. Implement web application firewalls (WAFs) with rules to detect and block reflected XSS payloads targeting the Nagios XI login page. 4. Conduct user awareness training to recognize and avoid clicking suspicious links, particularly those purporting to lead to Nagios XI login pages. 5. Review and harden Nagios XI configurations to minimize exposure, such as restricting access to the login page via VPN or IP whitelisting where feasible. 6. Monitor web server logs for unusual query parameters or repeated suspicious requests to the login page indicative of attempted exploitation. 7. Employ Content Security Policy (CSP) headers on the Nagios XI web server to restrict execution of inline scripts and reduce XSS impact. 8. Regularly audit and update legacy systems and browsers in the environment to reduce the attack surface for browser-based vulnerabilities.

Description

Nagios XI versions prior to < 2024R1.1.2 are vulnerable to a reflected cross-site scripting (XSS) via the login page when accessed with older web browsers. Insufficient validation or escaping of user-supplied input reflected by the login page can allow an attacker to craft a malicious link that, when visited by a victim, executes arbitrary JavaScript in the victim’s browser within the Nagios XI origin. The issue is observable under legacy browser behaviors; modern browsers may mitigate some vectors.

Impact

For European organizations, this vulnerability poses a moderate risk primarily to the confidentiality and integrity of user sessions and potentially the availability of monitoring services if exploited to inject malicious scripts. Attackers could leverage the XSS flaw to hijack sessions of administrators or users accessing Nagios XI via legacy browsers, leading to unauthorized access or manipulation of monitoring data. This could disrupt incident detection and response, delay remediation efforts, or cause false alarms. The impact is heightened in sectors with critical infrastructure monitored by Nagios XI, such as energy, telecommunications, and finance. Additionally, organizations with lax browser update policies or remote users relying on older browsers are more vulnerable. While the vulnerability does not directly compromise the underlying Nagios XI server or network, the ability to execute arbitrary scripts in users' browsers can facilitate phishing, credential theft, or lateral movement within the network. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers often weaponize such vulnerabilities post-disclosure. Therefore, European entities must consider the operational impact of potential exploitation and the risk to their monitoring integrity.

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 17 Nov 2025, 18:36 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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