How severe is CVE-2021-40511?

CVE-2021-40511 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-40511 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40511?

CVE-2021-40511 affects Obdasystems Mastro. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40511?

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

When was CVE-2021-40511 published?

CVE-2021-40511 was published on 2022-06-21 and last updated on 2026-06-17.

CVE-2021-40511

CVE-2021-40511 is a high-severity vulnerability in Obdasystems Mastro with a CVSS 3.x base score of 7.5. 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-776.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-776
Affected product: Obdasystems Mastro
Published: 2022-06-21
Last modified: 2026-06-17

Description

OBDA systems’ Mastro 1.0 is vulnerable to XML Entity Expansion (aka “billion laughs”) attack allowing denial of service.

Frequently asked questions

What is CVE-2021-40511?: OBDA systems’ Mastro 1.0 is vulnerable to XML Entity Expansion (aka “billion laughs”) attack allowing denial of service.
How severe is CVE-2021-40511?: CVE-2021-40511 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-40511 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40511?: CVE-2021-40511 affects Obdasystems Mastro. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40511?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-40511 published?: CVE-2021-40511 was published on 2022-06-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:obdasystems:mastro:1.0:*:*:*:*:*:*:*

More vulnerabilities in Obdasystems Mastro

CVE-2021-40510 — High (CVSS 7.5): XML eXternal Entity (XXE) in OBDA systems’ Mastro 1.0 allows remote attackers to read system files via custom DTDs.

All CVEs affecting Obdasystems Mastro →

Other CWE-776 vulnerabilities

CVE-2019-19144 — Critical (CVSS 9.8): XML External Entity Injection vulnerability in Quantum DXi6702 2.3.0.3 (11449-53631 Build304) devices via…
CVE-2022-23640 — Critical (CVSS 9.8): Excel-Streaming-Reader is an easy-to-use implementation of a streaming Excel reader using Apache POI. Prior to…
CVE-2014-2228 — Critical (CVSS 9.8): The XStream extension in HP Fortify SCA before 2.2 RC3 allows remote attackers to execute arbitrary code via unsafe…
CVE-2013-4335 — Critical (CVSS 9.8): opOpenSocialPlugin 0.8.2.1, > 0.9.9.2, 0.9.13, 1.2.6: Multiple XML External Entity Injection Vulnerabilities
CVE-2021-23926 — Critical (CVSS 9.1): The XML parsers used by XMLBeans up to version 2.6.0 did not set the properties needed to protect the user from…
CVE-2020-24590 — Critical (CVSS 9.1): The Management Console in WSO2 API Manager through 3.1.0 and API Microgateway 2.2.0 allows XML Entity Expansion attacks.

Browse all CWE-776 vulnerabilities →