VulnerabilityPublished 30 Oct 2025Updated 17 Nov 2025

CVE-2023-7323: Nagios Log Server · XSS or 'Cross-site Scripting'

Affects Nagios Log ServerSource CVE Database V5

Not known to be exploited · CVSS 5.1 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score

5.1Medium

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: Passive
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: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
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 26 Oct 2026.

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 or the CVSS exploit maturity 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 Log Server	Affected =0	Fixed in–

AI-suggested

Administrators should prioritize upgrading Nagios Log Server to version 2024R1 or later where the vulnerability is addressed. Until an official patch is available, organizations should implement strict input validation and output encoding on all user-supplied data within the Create User function to prevent script injection. Employing web application firewalls (WAFs) with rules designed to detect and block XSS payloads targeting Nagios interfaces can provide temporary protection. Additionally, restricting access to the Nagios Log Server interface to trusted networks and enforcing multi-factor authentication can reduce the risk of exploitation. Security teams should conduct user awareness training to mitigate the risk of social engineering attacks that could trigger user interaction. Regular monitoring of logs for suspicious activities and anomalous user behavior is recommended to detect potential exploitation attempts early. Finally, organizations should subscribe to Nagios security advisories to promptly apply future patches.

Description

CVE-2023-7323 is a medium-severity cross-site scripting (XSS) vulnerability affecting Nagios Log Server versions prior to 2024R1. The flaw exists in the Create User function due to improper neutralization of user input, allowing attackers to inject malicious scripts that execute in the victim's browser context. Exploitation requires low privileges and user interaction but no authentication. While no known exploits are currently reported in the wild, successful attacks could lead to session hijacking, credential theft, or unauthorized actions within the affected web application. European organizations using vulnerable Nagios Log Server versions are at risk, especially those in critical infrastructure and IT monitoring roles. Mitigation involves upgrading to version 2024R1 or later and implementing strict input validation and output encoding on user-supplied data. Countries with significant Nagios deployments and critical infrastructure monitoring, such as Germany, France, and the UK, are most likely to be affected. Due to the medium CVSS score and the nature of the vulnerability, organizations should prioritize patching to prevent potential exploitation.

Impact

For European organizations, especially those relying on Nagios Log Server for IT infrastructure monitoring and log management, this vulnerability poses a risk of unauthorized script execution within the administrative or user interface. Potential impacts include theft of session cookies, enabling attackers to impersonate legitimate users, unauthorized access to sensitive monitoring data, and manipulation of log data or user accounts. This could lead to disruption of monitoring capabilities, delayed detection of other security incidents, or escalation of privileges within the network. Critical infrastructure sectors such as energy, finance, and telecommunications, which heavily depend on continuous monitoring, could face operational risks and compliance issues if exploited. The requirement for user interaction somewhat limits mass exploitation but targeted phishing or social engineering attacks could facilitate exploitation. Overall, the vulnerability could undermine trust in monitoring systems and increase the attack surface for broader network compromise.

Summary

CVE-2023-7323 is a cross-site scripting (XSS) vulnerability classified under CWE-79 that affects Nagios Log Server versions prior to 2024R1. The vulnerability arises from insufficient validation or escaping of user-supplied input in the Create User function of the web interface. This improper neutralization allows an attacker to inject arbitrary JavaScript code, which executes in the context of a victim's browser when they interact with the affected interface. The CVSS 4.0 vector indicates the attack can be performed remotely over the network (AV:N) with low attack complexity (AC:L), no privileges required (PR:L indicates low privileges, but the description suggests no authentication is needed), and requires user interaction (UI:P). The vulnerability impacts confidentiality and integrity by enabling session hijacking, theft of sensitive information, or execution of unauthorized actions within the Nagios Log Server interface. Although no known exploits are reported in the wild, the presence of this vulnerability in monitoring infrastructure software is concerning because attackers could leverage it to gain further footholds or disrupt monitoring activities. The vulnerability is rated medium severity with a CVSS score of 5.1, reflecting moderate risk due to the need for user interaction and limited scope of impact. The lack of a published patch at the time of reporting necessitates immediate attention from administrators to apply available mitigations or upgrade once a fix is released.

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 24 Nov 2025, 22:18 UTC

WeaknessesCWE-79

Technical details

References

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