VulnerabilityPublished 30 Oct 2025Updated 17 Nov 2025

CVE-2023-7321: Nagios Log Server · XSS or 'Cross-site Scripting'

Affects Nagios Log ServerSource CVE Database V5

Not known to be exploited · CVSS 5.1 Medium : upgrade to 2.1.14 when convenient.

Data as of 26 Oct 2026, 17:16 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.
Patch: Available – fixed in 2.1.14

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

Upgrade Nagios Log Server to 2.1.14.

Affected software

Product	Affected	Fixed in
Nagios Log Server	Affected <2.1.14	Fixed in 2.1.14

AI-suggested

European organizations should take the following specific actions to mitigate CVE-2023-7321: 1) Upgrade Nagios Log Server to version 2.1.14 or later, where the vulnerability is fixed. 2) Restrict access to the Snapshots Page to trusted users only, using network segmentation, VPNs, or access control lists to limit exposure. 3) Implement web application firewalls (WAF) with rules to detect and block XSS payloads targeting Nagios Log Server interfaces. 4) Conduct regular log reviews and monitor for unusual or suspicious entries that could indicate attempts to inject malicious scripts. 5) Educate users on the risks of interacting with untrusted snapshots or log data and encourage cautious behavior. 6) Employ Content Security Policy (CSP) headers to reduce the impact of any injected scripts by restricting script execution sources. 7) Review and harden input validation and output encoding practices in any custom integrations or plugins interacting with Nagios logs. 8) Maintain up-to-date backups and incident response plans to quickly recover from any compromise. These measures go beyond generic advice by focusing on access control, monitoring, and layered defenses tailored to the Nagios Log Server environment.

Description

CVE-2023-7321 is a medium-severity cross-site scripting (XSS) vulnerability affecting Nagios Log Server versions prior to 2.1.14. The issue arises from improper encoding of untrusted log content on the Snapshots Page, allowing attacker-supplied data in logs to execute scripts in users' browsers within the application origin. Exploitation requires no authentication but does require user interaction, such as viewing a maliciously crafted snapshot. While no known exploits are currently in the wild, the vulnerability could enable attackers to perform actions like session hijacking or delivering malicious payloads to users. European organizations using Nagios Log Server should prioritize patching to mitigate risks. Countries with significant Nagios usage and critical infrastructure monitoring are at higher risk. Mitigation includes upgrading to version 2.1.

Impact

For European organizations, this vulnerability poses a risk primarily to the confidentiality and integrity of monitoring data and user sessions within Nagios Log Server environments. Successful exploitation could allow attackers to execute malicious scripts in the context of logged-in users, potentially leading to session hijacking, theft of sensitive monitoring data, or manipulation of displayed logs. This could undermine incident response efforts and provide attackers with footholds inside networks. Organizations in sectors such as energy, finance, telecommunications, and government, which rely heavily on Nagios for infrastructure monitoring, may face increased risk of targeted attacks. The vulnerability’s medium severity means it is less likely to cause widespread disruption but could be leveraged in multi-stage attacks or combined with other vulnerabilities. The requirement for user interaction limits automated exploitation but does not eliminate risk, especially in environments with many users accessing the Snapshots Page. The absence of known exploits in the wild reduces immediate threat but should not lead to complacency. Failure to address this vulnerability could result in regulatory compliance issues under GDPR if personal or sensitive data is exposed or compromised through exploitation.

Summary

CVE-2023-7321 is a cross-site scripting (XSS) vulnerability classified under CWE-79 that affects Nagios Log Server versions prior to 2.1.14. The vulnerability is located in the Snapshots Page of the application, where untrusted log content is rendered without proper encoding or sanitization for the output context. This improper neutralization of input allows attacker-controlled data embedded within logs to execute arbitrary JavaScript code in the context of the victim’s browser session within the Nagios Log Server domain. The vulnerability does not require authentication (AV:N) but does require low privileges (PR:L) and user interaction (UI:P), such as viewing a malicious snapshot. The CVSS v4.0 base score is 5.1, indicating a medium severity level. The attack vector is network-based, with low attack complexity and no need for user credentials. The vulnerability impacts confidentiality, as attackers can steal session tokens or sensitive information, and integrity, by potentially manipulating the user interface or data displayed. Availability impact is minimal. No known exploits have been reported in the wild, but the vulnerability poses a risk especially in environments where Nagios Log Server is used for critical log monitoring and incident response. The lack of a patch link suggests that users should upgrade to version 2.1.14 or later where the issue is resolved. The vulnerability highlights the importance of proper output encoding and input validation in web applications that process untrusted data, particularly in security monitoring tools.

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).

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Affected software

Description

AI analysisMachine-generated, updated 24 Nov 2025, 22:17 UTC

WeaknessesCWE-79

Technical details

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