CVE-2025-66037

low-risk
Published 2026-03-30

OpenSC is an open source smart card tools and middleware. Prior to version 0.27.0, feeding a crafted input to the fuzz_pkcs15_reader harness causes OpenSC to perform an out-of-bounds heap read in the X.509/SPKI handling path. Specifically, sc_pkcs15_pubkey_from_spki_fields() allocates a zero-length buffer and then reads one byte past the end of that allocation. This issue has been patched in version 0.27.0.

Do I need to act?

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0.01% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
3
CVSS 3.9/10 Low
PHYSICAL / HIGH complexity

Affected Products (1)

Affected Vendors

Opensc Project

References (2)

Exploit https://github.com/OpenSC/OpenSC/security/advisories/GHSA-m58q-rmjm-mmfx
Vendor Advisory https://github.com/OpenSC/OpenSC/wiki/CVE-2025-66037
15
/ 100
low-risk
Severity 10/34 · Low
Exploitability 0/34 · Minimal
Exposure 5/34 · Minimal