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CVE-2025-66038

low

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.

3.9
cvss low
common vulnerability scoring system v3.1. measures intrinsic severity on a 0-10 scale.
epss 0.0002
exploitation prediction scoring system. probability this vulnerability will be exploited in the wild in the next 30 days.
kev no
cisa known exploited vulnerabilities catalog. confirmed active exploitation.
CVSS 3.1 Common Vulnerability Scoring System v3.1
3.9 / 10
LOW
exploitability
Attack Vector
Physical
Attack Vector (AV:P): requires physical access to the hardware.
Attack Complexity
High
Attack Complexity (AC:H): exploitation requires specific conditions outside the attacker's control (race condition, non-default config, etc).
Privileges Required
None
Privileges Required (PR:N): no authentication needed. any anonymous attacker can exploit this.
User Interaction
None
User Interaction (UI:N): no victim action needed. fully exploitable without user interaction.
impact
Scope
Unchanged
Scope (S:U): impact limited to the vulnerable component.
Confidentiality
Low
Confidentiality (C:L): limited data exposure. some restricted information can be read.
Integrity
Low
Integrity (I:L): limited data modification. some data can be altered.
Availability
Low
Availability (A:L): reduced performance or partial service interruption.
CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
exploit detect attrib advisory media timeline
exploitation detection attribution advisories media timeline
activity density
rdintel assessment
17 threat composite score from 15+ signals including exploitation status, epss probability, detection coverage, and community attention. 0-100 scale.

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