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.
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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 |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-03-30T17:03:55.914Z
Reserved: 2025-11-21T01:08:02.615Z
Link: CVE-2025-66038
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Status : Received
Published: 2026-03-30T18:16:18.177
Modified: 2026-03-30T18:16:18.177
Link: CVE-2025-66038
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Weaknesses