CVE-2020-26571 [Medium] | Out-of-bounds Write in Opensc

CVE-2020-26571 is rated Low Risk (33.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.40%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.04%	0.40%	+0.35%
2	2025-11-21	0.09%	0.04%	-0.04%
3	2025-11-18	—	0.09%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.04%

0.40%

+0.35%

2025-11-21

0.09%

0.04%

-0.04%

2025-11-18

—

0.09%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. 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:L) A normal user session is enough; they don’t have to be admin. 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:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]
2.1	2.0	LOW	`AV:L/AC:L/Au:N/C:N/I:N/A:P` Click to expand Access vector (AV:L) Requires local access to the target system. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	3.9	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

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

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:L): A normal user session is enough; they don’t have to be admin.
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:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

2.1

2.0

LOW

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

Access vector (AV:L): Requires local access to the target system.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

3.9

2.9

[email protected]

OS Trackers for CVE-2020-26571

vendor	priority	summary	link
`alpine`	medium	CVE-2020-26571: 1 source package rows (opensc); 11 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 4.	https://security.alpinelinux.org/vuln/CVE-2020-26571
`debian`	not yet assigned	CVE-2020-26571 not yet assigned priority: Debian including 1 source packages (opensc), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2020-26571
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2020-26571
`suse`	medium	CVE-2020-26571 severity moderate: SUSE including 21 source package names (libopensc2-0.11.6-5.27.9.1, libopensc2-32bit-0.11.6-5.27.9.1, …), 36 product×package rows across 27 product lines (SUSE Liberty Linux 8, SUSE Linux Enterprise High Performance Computing 15-ESPOS, … (27 product lines)): Fixed 35, Known Not Affected 1.	https://www.suse.com/security/cve/CVE-2020-26571/
`ubuntu`	medium	CVE-2020-26571 medium priority: Ubuntu including 1 source packages (opensc), 15 status rows across 15 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 8, released 3, ignored 2, DNE 1, needs-triage 1.	https://ubuntu.com/security/CVE-2020-26571

Affected software / configurations for CVE-2020-26571

Vendor	Product	Version	Raw CPE
opensc_project	opensc	<= 0.20.0	cpe:2.3:a:opensc_project:opensc::::::::
debian	debian_linux	9.0	cpe:2.3:o:debian:debian_linux:9.0:::::::*
fedoraproject	fedora	33	cpe:2.3:o:fedoraproject:fedora:33:::::::*

References for CVE-2020-26571

URL	Tags
http://www.openwall.com/lists/oss-security/2020/11/24/4	Mailing List Third Party Advisory
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=20612	Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/11/msg00027.html	Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EXOHFDMNMO6IDECAGUTB3SJGAGXVRT6S/

URL

CVE-2020-26571

Exploit prediction scoring system (EPSS) score for CVE-2020-26571

Common vulnerability scoring system (CVSS) metrics for CVE-2020-26571

Weakness enumeration for CVE-2020-26571

OS Trackers for CVE-2020-26571

Affected software / configurations for CVE-2020-26571

References for CVE-2020-26571