How severe is CVE-2021-40353?

CVE-2021-40353 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-40353 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40353?

CVE-2021-40353 affects Os4ed Opensis. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40353?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-40353 published?

CVE-2021-40353 was published on 2021-09-01 and last updated on 2026-06-17.

CVE-2021-40353

CVE-2021-40353 is a critical-severity vulnerability in Os4ed Opensis with a CVSS 3.x base score of 9.8. 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-89.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-89
Affected product: Os4ed Opensis
Published: 2021-09-01
Last modified: 2026-06-17

Description

A SQL injection vulnerability exists in version 8.0 of openSIS when MySQL or MariaDB is used as the application database. An attacker can then issue the SQL command through the index.php USERNAME parameter. NOTE: this issue may exist because of an incomplete fix for CVE-2020-6637.

Frequently asked questions

What is CVE-2021-40353?: A SQL injection vulnerability exists in version 8.0 of openSIS when MySQL or MariaDB is used as the application database. An attacker can then issue the SQL command through the index.php USERNAME parameter. NOTE: this issue may exist because of an incomplete fix for CVE-2020-6637.
How severe is CVE-2021-40353?: CVE-2021-40353 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-40353 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40353?: CVE-2021-40353 affects Os4ed Opensis. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40353?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-40353 published?: CVE-2021-40353 was published on 2021-09-01 and last updated on 2026-06-17.

References

Affected products (1)

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

More vulnerabilities in Os4ed Opensis

CVE-2021-41691 — Critical (CVSS 9.8): A SQL injection vulnerability exists in OS4Ed Open Source Information System Community v8.0 via the "student_id" and…
CVE-2025-22930 — Critical (CVSS 9.8): OS4ED openSIS v7.0 to v9.1 was discovered to contain a SQL injection vulnerability via the groupid parameter at…
CVE-2025-22929 — Critical (CVSS 9.8): OS4ED openSIS v7.0 to v9.1 was discovered to contain a SQL injection vulnerability via the filter_id parameter at…
CVE-2025-22926 — Critical (CVSS 9.8): An issue in OS4ED openSIS v8.0 through v9.1 allows attackers to execute a directory traversal by sending a crafted POST…
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…
CVE-2024-51211 — Critical (CVSS 9.8): SQL injection vulnerability exists in OS4ED openSIS-Classic Version 9.1, specifically in the resetuserinfo.php file.…

All CVEs affecting Os4ed Opensis →

Other CWE-89 (SQL Injection) vulnerabilities

CVE-2026-54350 — Critical (CVSS 10.0): Budibase is an open-source low-code platform. Prior to 3.39.12, an unauthenticated visitor of any published Budibase…
CVE-2026-8054 — Critical (CVSS 10.0): Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') in the Publish Audit API endpoints…
CVE-2026-42287 — Critical (CVSS 10.0): Emlog is an open source website building system. Prior to version 2.6.11, direct SQL injection in article creation and…
CVE-2026-3325 — Critical (CVSS 10.0): SQL injection (SQLi) in MegaCMS v12.0.0, specifically in the “id_territorio” parameter of the…
CVE-2025-10878 — Critical (CVSS 10.0): A SQL injection vulnerability exists in the login functionality of Fikir Odalari AdminPando 1.0.1 before 2026-01-26.…
CVE-2025-57792 — Critical (CVSS 10.0): Explorance Blue versions prior to 8.14.9 contain a SQL injection vulnerability caused by insufficient validation of…

Browse all CWE-89 (SQL Injection) vulnerabilities →