OpenSC is an open source smart card tools and middleware. Prior to version 0.27.0, sc_compacttlv_find_tag searches a compact-TLV buffer for a given tag. In compact-TLV, a single byte encodes the tag (high nibble) and value length (low nibble). With a 1-byte buffer {0x0A}, the encoded element claims tag=0 and length=10 but no value bytes follow. Calling sc_compacttlv_find_tag with search tag 0x00 returns a pointer equal to buf+1 and outlen=10 without verifying that the claimed value length fits within the remaining buffer. In cases where the sc_compacttlv_find_tag is provided untrusted data (such as being read from cards/files), attackers may be able to influence it to return out-of-bounds pointers leading to downstream memory corruption when subsequent code tries to dereference the pointer. This issue has been patched in version 0.27.0.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Mon, 30 Mar 2026 17:30:00 +0000

Type Values Removed Values Added
Description OpenSC is an open source smart card tools and middleware. Prior to version 0.27.0, sc_compacttlv_find_tag searches a compact-TLV buffer for a given tag. In compact-TLV, a single byte encodes the tag (high nibble) and value length (low nibble). With a 1-byte buffer {0x0A}, the encoded element claims tag=0 and length=10 but no value bytes follow. Calling sc_compacttlv_find_tag with search tag 0x00 returns a pointer equal to buf+1 and outlen=10 without verifying that the claimed value length fits within the remaining buffer. In cases where the sc_compacttlv_find_tag is provided untrusted data (such as being read from cards/files), attackers may be able to influence it to return out-of-bounds pointers leading to downstream memory corruption when subsequent code tries to dereference the pointer. This issue has been patched in version 0.27.0.
Title OpenSC: `sc_compacttlv_find_tag` can return out-of-bounds pointers
Weaknesses CWE-126
References
Metrics cvssV3_1

{'score': 3.9, 'vector': 'CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-30T17:03:55.914Z

Reserved: 2025-11-21T01:08:02.615Z

Link: CVE-2025-66038

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-30T18:16:18.177

Modified: 2026-03-30T18:16:18.177

Link: CVE-2025-66038

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses