VulnerabilityPublished 14 Nov 2026

CVE-2026-129251: hrshadhin CloudSchool · Cross-site Scripting

Affects hrshadhin CloudSchoolSource CVE Database V5

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Public exploit available · CVSS 4.8 Medium.

Data as of 14 Nov 2026, 12:08 UTC

CVSS 4.0 base score

4.8Medium

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (VulDB)	CVSS 4.0	4.8
CNA (VulDB)	CVSS 3.1	2.4
CNA (VulDB)	CVSS 3.0	2.4
CNA (VulDB)	CVSS 2.0	3.3

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 14 Nov 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 14 Nov 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
hrshadhinCloudSchool	Affected =3.0.0 =3.0.1	Fixed in–

CPE configurations (1)

cpe:2.3:a:hrshadhin:cloudschool:*:*:*:*:*:*:*:*

AI-suggested

Users should consider restricting access to the affected versions (3.0.0 and 3.0.1) and apply web application firewall (WAF) rules to detect and block XSS payloads targeting the Event Description Handler. Monitor for any future vendor advisories or patches and apply them promptly once available.

Description

CVE-2026-129251 is a cross-site scripting (XSS) vulnerability in hrshadhin CloudSchool versions 3.0.0 and 3.0.1. The flaw exists in the Event Description Handler component within the file app/Http/Controllers/Backend/EventController.php. An attacker can remotely exploit this vulnerability by manipulating input data, potentially leading to XSS attacks. Public exploit code is available, but there is no vendor response or patch provided as of the publication date.

Impact

Successful exploitation allows remote attackers with high privileges to perform cross-site scripting attacks by injecting malicious scripts into the affected component. This can lead to user interface manipulation and potential information disclosure in the context of the affected application. The vulnerability requires user interaction and high privileges, limiting the scope but still posing a risk to affected users.

Summary

This vulnerability affects hrshadhin CloudSchool up to version 3.0.1 in the Event Description Handler component. Specifically, the vulnerability arises from improper sanitization of an argument in the EventController.php file, allowing remote attackers to inject malicious scripts via cross-site scripting. The vulnerability has a CVSS 4.8 (medium) score, indicating a moderate risk with network attack vector, low attack complexity, and requiring high privileges and user interaction.

References

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