# CVE-2026-103531: OpenSC card-setcos.c setcos_construct_fci_44 stack-based overflow

CVE-2026-103531 is fixed in opensc on 1 platform by DEBIAN-CVE-2026-103531 (version 0.27.1-3), released October 10, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-103531
- Priority: Routine
- CVSS: 5.5 (Moderate)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 1, 2026
- Weakness: Stack-based Buffer Overflow
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-103531

## Description

A flaw has been found in OpenSC up to 0.27.1. The impacted element is the function setcos_construct_fci_44 of the file src/libopensc/card-setcos.c. Executing a manipulation of the argument type_attr can lead to stack-based buffer overflow. The attack can be launched remotely. This patch is called ad730304052937c32b4eb489a06835ac6123632c. It is best practice to apply a patch to resolve this issue.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | opensc Debian 14 | 0.27.1-3 | [DEBIAN-CVE-2026-103531](https://patchblox.com/security/data/fix/linux/debian-cve-2026-103531.md) | Oct 10, 2026 |

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Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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