Is CVE-2021-22156 in the CISA KEV catalog?

No. CVE-2021-22156 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-22156?

CVE-2021-22156 has a CVSS v3 base score of 9.0 (CRITICAL).

What is the EPSS score for CVE-2021-22156?

CVE-2021-22156 has an EPSS score of 1.80% (76th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-22156?

Upgrade qnx software development platform to 6.5.0 or later.

CVE & CISA-KEV Catalog

CVE-2021-22156

CRITICALEPSS 76th pctl

9.0

CVSS v3

NVD

Description

An integer overflow vulnerability in the calloc() function of the C runtime library of affected versions of BlackBerry® QNX Software Development Platform (SDP) version(s) 6.5.0SP1 and earlier, QNX OS for Medical 1.1 and earlier, and QNX OS for Safety 1.0.1 and earlier that could allow an attacker to potentially perform a denial of service or execute arbitrary code.

CWE-190Integer Overflow

How to fix

Remediation Available

qnx software development platformNVD

Affected:< 6.5.0Fixed in:6.5.0CVE-2021-22156derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploit Intelligence

1.80%probability of exploitation in 30 days

76thpercentile

Elevated risk: more likely to be exploited than 76% of all known CVEs.

References

Patch1

support.blackberry.com

Third-Party Advisory1

tools.cisco.com

Related Vulnerabilities

Other CWE-190 (Integer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-16040	Medium	6.5	100%	-	Fix
CVE-2019-11477	High	7.5	99%	-	Fix
CVE-2023-44443	High	7.8	94%	-	Fix
CVE-2014-0569	High	9.3	90%	-	-
CVE-2017-3599	High	7.5	90%	-	Fix
CVE-2023-21716	Critical	9.8	82%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-08-22.