VulnerabilityPublished 26 Dec 2025Updated 24 Feb 2026

CVE-2025-15094: sunkaifei FlyCMS · Cross-site Scripting

Affects sunkaifei FlyCMSSource CVE Database V5

Public exploit available · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 4.0 base score

5.3Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 33% 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:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

Base metrics

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

Threat metrics

Exploit Maturity: POC

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: 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: 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 Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable 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.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: proof of concept public
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), CVSS vector, 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

AI-suggested

Organizations should immediately implement input validation and output encoding for the redirectUrl parameter to neutralize malicious scripts. If source code modification is possible, sanitize the redirectUrl input by allowing only safe URLs or using a whitelist approach. Employ Content Security Policy (CSP) headers to restrict script execution and reduce XSS impact. Monitor web server logs for suspicious requests containing script payloads targeting redirectUrl. If FlyCMS is deployed behind a web application firewall (WAF), configure rules to detect and block XSS attempts in URL parameters. Educate users to avoid clicking suspicious links and report unusual login page behavior. Regularly check for vendor updates or community patches. Additionally, implement multi-factor authentication (MFA) to mitigate the impact of credential theft resulting from XSS attacks. Finally, conduct security assessments and penetration tests focusing on input validation in FlyCMS installations.

Description

A weakness has been identified in sunkaifei FlyCMS up to abbaa5a8daefb146ad4d61027035026b052cb414. The impacted element is the function userLogin of the file src/main/java/com/flycms/web/front/UserController.java of the component User Login. Executing a manipulation of the argument redirectUrl can lead to cross site scripting. The attack can be launched remotely. The exploit has been made available to the public and could be used for attacks. This product does not use versioning. This is why information about affected and unaffected releases are unavailable. The project was informed of the problem early through an issue report but has not responded yet.

Impact

The vulnerability allows attackers to execute arbitrary JavaScript in the context of users visiting a maliciously crafted URL, potentially leading to session hijacking, theft of sensitive information such as credentials, or redirection to phishing sites. This can undermine user trust and compromise the security of websites running FlyCMS. Since the flaw exists in the login component, successful exploitation could facilitate unauthorized access or persistent attacks against user accounts. Organizations relying on FlyCMS for content management and user authentication face risks of data breaches, reputational damage, and regulatory consequences if user data is compromised. The lack of vendor response and patch availability increases exposure time, raising the likelihood of exploitation. Although no widespread exploitation is currently reported, the public exploit availability means opportunistic attackers could target vulnerable installations. The impact is primarily on confidentiality and integrity, with limited direct availability impact. Overall, this vulnerability poses a moderate risk to organizations using FlyCMS, especially those with high user interaction or sensitive data.

Summary

CVE-2025-15094 identifies a cross-site scripting (XSS) vulnerability in FlyCMS, specifically in the userLogin function located in src/main/java/com/flycms/web/front/UserController.java. The vulnerability is triggered by manipulation of the redirectUrl parameter, which is not properly sanitized or validated before being reflected in the application's response. This flaw allows remote attackers to inject arbitrary JavaScript code that executes in the context of the victim's browser when they interact with a crafted URL. The vulnerability requires no authentication and can be exploited remotely, but user interaction is necessary to trigger the malicious script. The vulnerability has a CVSS 4.0 base score of 5.3, reflecting medium severity, with attack vector network, low attack complexity, no privileges required, and user interaction needed. The impact primarily affects confidentiality and integrity by enabling session hijacking, credential theft, or phishing attacks. The vendor sunkaifei has been notified but has not responded or issued a patch, and FlyCMS does not use versioning, complicating identification of unaffected versions. The public availability of an exploit increases the risk of exploitation in the wild. This vulnerability highlights the importance of input validation and output encoding in web applications, especially in login workflows where redirect parameters are common.

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 24 Feb 2026, 22:30 UTC

Technical details

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