CVE-2025-66038Public exploit

Application crash via unchecked compact-TLV length

Published Mar 30, 2026 · Updated Mar 30, 2026

Buffer over-read in OpenSC before 0.27.0 allows physically proximate attackers to crash applications via crafted smart-card data. The sc_compacttlv_find_tag function returns a value pointer and attacker-declared length without checking that the compact-TLV value fits in the remaining buffer. Exploitation requires a crafted smart card or USB device to supply malformed historical bytes, after which a consumer can read beyond the buffer, corrupt memory, or crash.

CVSS severity3.9
Low
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer over-read in OpenSC before 0.27.0 allows physically proximate attackers to crash applications via crafted smart-card data. The sc_compacttlv_find_tag function returns a value pointer and attacker-declared length without checking that the compact-TLV value fits in the remaining buffer. Exploitation requires a crafted smart card or USB device to supply malformed historical bytes, after which a consumer can read beyond the buffer, corrupt memory, or crash.

The record

CVE
CVE-2025-66038
Published
Mar 30, 2026
Updated
Mar 30, 2026
Vendor
OpenSC Project
Product
OpenSC
Classifications
CWE-126, T1200
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.27.0

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

OpenSC Project · OpenSCversion=< 0.27.0

Published CVSS scores

6.8NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.9GitHub, Inc.CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-126Buffer Over-read
T1200Hardware Additions

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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