Is CVE-2026-40528 in the CISA KEV catalog?

No. CVE-2026-40528 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-40528?

CVE-2026-40528 has a CVSS v3 base score of 3.8 (Low).

What is the EPSS score for CVE-2026-40528?

CVE-2026-40528 has an EPSS score of 0.15% (4th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-40528?

Upgrade opensc to 0.27.0 or later.

CVE & CISA-KEV Catalog

CVE-2026-40528

LOW

3.8

CVSS v3

NVD

Description

OpenSC before 0.27.0, fixed in commit 0358817, contains a stack and heap buffer overrun vulnerability in the do_key_value() function in src/pkcs15init/profile.c that allows attackers to corrupt memory by supplying a crafted profile configuration file. During pkcs15-init invocation, a key value entry beginning with '=' followed by more than sizeof(keybuf) characters is copied into keybuf via memcpy without a length check, causing both stack and heap buffer overruns.

CWE-121Stack-based Buffer Overflow CWE-122Heap-based Buffer Overflow

How to fix

Remediation Available

openscNVD

Affected:< 0.27.0Fixed in:0.27.0CVE-2026-40528derived 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 VectorPhysical

Attack ComplexityHigh

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityLow

CVSS:3.1/AV:P/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L

Exploit Intelligence

0.15%probability of exploitation in 30 days

4thpercentile

Low risk: more likely to be exploited than 4% of all known CVEs.

References

Patch1

github.com

Third-Party Advisory1

vulncheck.com

Related Vulnerabilities

Other CWE-121 (Stack-based Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-22457	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2025-0282	Critical	9.0	100%	KEV + Ransom	-
CVE-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2009-0927	High	8.8	97%	KEV	Fix
CVE-2020-10924	High	8.8	87%	-	-
CVE-2022-20705	Critical	10.0	80%	-	-

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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 2026-06-03.