CVE-2026-40528: OpenSC < 0.27.0 Buffer Overrun in do_key_value() via profile.c

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-29 · updated 2026-07-21
Weakness: CWE-121

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.

Affected products

OpenSC: before 0.27.0 — fixed in 0.27.0

How to fix

Upgrade to a fixed version: OpenSC 0.27.0. Check the vendor advisory for mitigations.

References

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