CVE-2026-40528

Memory corruption via unchecked profile key length

Published May 29, 2026 · Updated May 29, 2026

Buffer overflow in OpenSC before 0.27.0 allows physically proximate attackers to corrupt memory through a crafted profile file. The do_key_value() function copies an equals-prefixed key into keybuf with memcpy without first limiting the key length to the buffer size. The file must be parsed during a pkcs15-init invocation; published evidence establishes stack and heap corruption but not code execution.

CVSS severity1.0
Low
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in OpenSC before 0.27.0 allows physically proximate attackers to corrupt memory through a crafted profile file. The do_key_value() function copies an equals-prefixed key into keybuf with memcpy without first limiting the key length to the buffer size. The file must be parsed during a pkcs15-init invocation; published evidence establishes stack and heap corruption but not code execution.

The record

CVE
CVE-2026-40528
Published
May 29, 2026
Updated
May 29, 2026
Vendor
OpenSC Project
Product
OpenSC
Classifications
CWE-122, CWE-121, T1204.002
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 29, 2026CVE publishedPublication date reported by the CVE source.
  2. May 29, 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 <0.27.0
  2. Affected versionversion=0 <0358817ec74aeca654f83e7709c7720b14c5db59

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

OpenSC Project · OpenSCversion=0 <0.27.0; version=0 <0358817ec74aeca654f83e7709c7720b14c5db59

Published CVSS scores

1.0VulnCheckCVSS:4.0/AV:P/AC:H/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
3.8VulnCheckCVSS:3.1/AV:P/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-121Stack-based Buffer Overflow
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

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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