CVE-2021-40310Public exploitNetwork attack vector

Authenticated script execution via unescaped attendance parameter

Published Sep 24, 2021 · Updated Aug 4, 2024

Reflected XSS in OS4ED openSIS Community Edition 8.0 allows remote authenticated users to execute script via cp_id_miss_attn. TakeAttendance.php reflects the parameter into an exported attendance page without neutralizing attacker-supplied HTML attributes. A teacher account and victim interaction with a crafted URL are required; the script runs in the openSIS origin and can read or alter browser-accessible data.

CVSS severity5.4
Medium
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in OS4ED openSIS Community Edition 8.0 allows remote authenticated users to execute script via cp_id_miss_attn. TakeAttendance.php reflects the parameter into an exported attendance page without neutralizing attacker-supplied HTML attributes. A teacher account and victim interaction with a crafted URL are required; the script runs in the openSIS origin and can read or alter browser-accessible data.

The record

CVE
CVE-2021-40310
Published
Sep 24, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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