CVE-2026-40510: OpenSC < 0.27.0-rc1 Stack Buffer Overflow via piv_process_history() in card-piv.c

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.3%

EPSS score, percentile 22 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

1.0 Low

CVSS v4.0 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

• before 0.27.0-rc1

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Advisories and patches

• github.com (Patch)

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: affected.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

OpenSC before 0.27.0-rc1, fixed in commit 3f24f0b, contains a stack buffer overflow vulnerability in piv_process_history() in src/libopensc/card-piv.c that allows physically present attackers to trigger memory corruption by presenting a crafted PIV smart card or USB device returning a URL field longer than 118 bytes in the Key History Object ASN.1 response.

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-40510 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 29 May 2026.
• The CVE record carries a CVSS v4.0 base score of 1.0 (Low), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.3% (percentile 22), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
• The credits in the CVE record name Anthropic (Claude) as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

OpenSC < 0.27.0-rc1 Stack Buffer Overflow via piv_process_history() in card-piv.c

OpenSC before 0.27.0-rc1, fixed in commit 3f24f0b, contains a stack buffer overflow vulnerability in piv_process_history() in src/libopensc/card-piv.c that allows physically present attackers to trigger memory corruption by presenting a crafted PIV smart card or USB device returning a URL field longer than 118 bytes in the Key History Object ASN.1 response.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline