VulnerabilityPublished 30 Mar 2026

CVE-2026-30562: Web-Security-PoCs · Cross-site Scripting

Affects Web-Security-PoCsSource CVE Database V5

Not known to be exploited · CVSS 9.3 Critical.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

9.3Critical

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: High
Integrity: High
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 Mar 2026
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
GitHubmeifukun/Web-Security-PoCs`pkg:github/meifukun/Web-Security-PoCs`Other threats	Affected =1.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate this vulnerability, organizations should first check for and apply any official patches or updates released by the vendor for SourceCodester Sales and Inventory System 1.0. In the absence of patches, implement strict input validation on the 'msg' parameter to reject or sanitize any input containing HTML or JavaScript code. Employ output encoding techniques such as HTML entity encoding before reflecting user input back to the browser to prevent script execution. Use Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts. Conduct regular security assessments and penetration tests focusing on input validation and XSS vulnerabilities. Educate users to avoid clicking suspicious links and implement web application firewalls (WAFs) that can detect and block XSS attack patterns. Additionally, review and harden session management to minimize the impact of potential session hijacking. Logging and monitoring for unusual web requests targeting the 'msg' parameter can help detect exploitation attempts early.

Description

A Reflected Cross-Site Scripting (XSS) vulnerability exists in SourceCodester Sales and Inventory System 1.0. The vulnerability is located in the add_stock.php file via the "msg" parameter. The application fails to sanitize the input, allowing remote attackers to inject arbitrary web script or HTML via a crafted URL.

Impact

The primary impact of this vulnerability is on the confidentiality and integrity of user sessions and data. Attackers exploiting this reflected XSS can hijack user sessions, steal sensitive information such as authentication tokens, or manipulate the web interface to perform unauthorized actions. This can lead to unauthorized access, data leakage, or reputational damage for organizations. Additionally, users may be redirected to malicious websites, increasing the risk of malware infections or phishing attacks. Since the vulnerability does not require authentication and can be triggered via a crafted URL, it poses a significant risk to all users interacting with the vulnerable system. The availability impact is generally low unless combined with other vulnerabilities. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as the vulnerability is publicly disclosed. Organizations using the affected software, particularly those managing inventory and sales data, face risks of operational disruption and data compromise.

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

github.com/meifukun/Web-Security-PoCs/blob/main/Inventory-System/XSS-AddStock-msg.md (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Mar 2026, 16:09 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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