VulnerabilityPublished 31 Mar 2026

CVE-2026-5209: SourceCodester Leave Application System · Cross-site Scripting

Affects SourceCodester Leave Application SystemSource CVE Database V5

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Public exploit available · CVSS 4.8 Medium.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score

4.8Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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: High
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: High: The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.
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 31 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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
SourceCodesterLeave Application System	Affected =1.0	Fixed in–

AI-suggested

Organizations should immediately assess their use of SourceCodester Leave Application System version 1.0 and plan for an upgrade or patch deployment once available. In the absence of an official patch, implement strict input validation and sanitization on all user inputs, especially within the User Management Handler component. Deploy web application firewalls (WAFs) with custom rules to detect and block typical XSS payloads targeting this application. Conduct security awareness training to educate users about the risks of clicking on suspicious links or executing unexpected scripts. Regularly monitor application logs for unusual activities indicative of attempted exploitation. Consider isolating the affected system within the network to limit exposure. Additionally, review and enforce the principle of least privilege to minimize the number of users with high privileges required for exploitation. Engage with the vendor or community to track patch releases and apply them promptly. Finally, perform regular security assessments and penetration testing focused on web application vulnerabilities to detect similar issues proactively.

Description

A security vulnerability has been detected in SourceCodester Leave Application System 1.0. Affected by this issue is some unknown functionality of the component User Management Handler. Such manipulation leads to cross site scripting. The attack may be launched remotely. The exploit has been disclosed publicly and may be used.

Impact

The primary impact of CVE-2026-5209 is the potential for attackers to execute malicious scripts within the context of authenticated users of the Leave Application System, leading to session hijacking, theft of sensitive information, or unauthorized actions within the application. This can compromise user confidentiality and data integrity. Although the vulnerability does not directly affect system availability, successful exploitation could facilitate further attacks or unauthorized access. Organizations relying on this software for employee leave management may face operational disruptions, reputational damage, and compliance risks if sensitive HR data is exposed or manipulated. The requirement for high privileges and user interaction limits the ease of exploitation, reducing the overall risk but not eliminating it. The public disclosure without an available patch increases the urgency for organizations to implement compensating controls. Attackers could leverage this vulnerability as part of a broader attack chain targeting internal HR systems, which often contain personally identifiable information (PII) and other sensitive data.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 31 Mar 2026, 18:53 UTC

Technical details

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