CVE-2026-40528

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.

CVSS v3.1 Score

3.8

LOW

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

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-121 CWE-121

CWE-122 CWE-122

Affected Products

Vendor	Product	Versions
opensc_project	opensc	< 0.27.0

References

Advisories & Patches

https://github.com/OpenSC/OpenSC/commit/0358817ec74aeca654f83e7709c7720b14c5db59

Other References

https://www.vulncheck.com/advisories/opensc-buffer-overrun-in-do-key-value-via-profile-c

Frequently Asked Questions

What is CVE-2026-40528? +

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. It has a CVSS v3.1 base score of 3.8 (LOW).

How severe is CVE-2026-40528? +

CVE-2026-40528 has a CVSS v3.1 score of 3.8 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-40528? +

CVE-2026-40528 affects products from opensc_project, specifically: opensc. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-40528? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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