How severe is CVE-2021-40310?

CVE-2021-40310 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-40310 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40310?

CVE-2021-40310 affects Os4ed Opensis. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40310?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-40310 published?

CVE-2021-40310 was published on 2021-09-24 and last updated on 2026-06-17.

CVE-2021-40310

CVE-2021-40310 is a medium-severity vulnerability in Os4ed Opensis with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Os4ed Opensis
Published: 2021-09-24
Last modified: 2026-06-17

Description

OpenSIS Community Edition version 8.0 is affected by a cross-site scripting (XSS) vulnerability in the TakeAttendance.php via the cp_id_miss_attn parameter.

Frequently asked questions

What is CVE-2021-40310?: OpenSIS Community Edition version 8.0 is affected by a cross-site scripting (XSS) vulnerability in the TakeAttendance.php via the cp_id_miss_attn parameter.
How severe is CVE-2021-40310?: CVE-2021-40310 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-40310 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40310?: CVE-2021-40310 affects Os4ed Opensis. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40310?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-40310 published?: CVE-2021-40310 was published on 2021-09-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:os4ed:opensis:8.0:*:*:*:community:*:*:*

More vulnerabilities in Os4ed Opensis

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CVE-2025-22928 — Critical (CVSS 9.8): OS4ED openSIS v7.0 to v9.1 was discovered to contain a SQL injection vulnerability via the cp_id parameter at…
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