CVE-2021-22156 [Critical] | Integer Overflow in Qnx Software Development …

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-02-25	1.28%	0.89%	-0.39%
2	2025-11-21	1.10%	1.28%	+0.18%
3	2025-11-18	—	1.10%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-02-25

1.28%

0.89%

-0.39%

2025-11-21

1.10%

1.28%

+0.18%

2025-11-18

—

1.10%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.0	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.2	6.0	[email protected]
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.9	[email protected]
6.8	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:P/I:P/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	8.6	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.0

3.1

CRITICAL

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

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.2

6.0

[email protected]

9.8

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.9

[email protected]

6.8

2.0

MEDIUM

AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:M): Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

8.6

6.4

[email protected]

Affected software / configurations for CVE-2021-22156

Vendor	Product	Version	Raw CPE
blackberry	qnx_software_development_platform	< 6.5.0	cpe:2.3:a:blackberry:qnx_software_development_platform::::::::
blackberry	qnx_software_development_platform	6.5.0	cpe:2.3:a:blackberry:qnx_software_development_platform:6.5.0:-::::::
blackberry	qnx_software_development_platform	6.5.0	cpe:2.3:a:blackberry:qnx_software_development_platform:6.5.0:sp1::::::
blackberry	qnx_os_for_medical	<= 1.1.1	cpe:2.3:o:blackberry:qnx_os_for_medical::::::::
blackberry	qnx_os_for_safety	<= 1.0.2	cpe:2.3:o:blackberry:qnx_os_for_safety::::::::

References for CVE-2021-22156

URL	Tags
https://support.blackberry.com/kb/articleDetail?articleNumber=000082334	Patch Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-qnx-TOxjVPdL	Third Party Advisory

URL

CVE-2021-22156

Exploit prediction scoring system (EPSS) score for CVE-2021-22156

Common vulnerability scoring system (CVSS) metrics for CVE-2021-22156

Weakness enumeration for CVE-2021-22156

Affected software / configurations for CVE-2021-22156

References for CVE-2021-22156