CVE-2026-40253Public exploit

Memory disclosure via unchecked BER length fields

Published Apr 16, 2026 · Updated Apr 16, 2026

Out-of-bounds reads in openCryptoki 3.26.0 and earlier allow local users to disclose process memory via malformed BER objects. The shared asn1.c decoders accept no buffer length and trust BER length fields; ber_decode_INTEGER also subtracts from a zero length. Reachability requires a malformed key or certificate through PKCS#11 import or unwrap operations, disk-loaded tokens, or remote backends; effects include process-memory disclosure and service interruption.

CVSS severity6.8
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds reads in openCryptoki 3.26.0 and earlier allow local users to disclose process memory via malformed BER objects. The shared asn1.c decoders accept no buffer length and trust BER length fields; ber_decode_INTEGER also subtracts from a zero length. Reachability requires a malformed key or certificate through PKCS#11 import or unwrap operations, disk-loaded tokens, or remote backends; effects include process-memory disclosure and service interruption.

The record

CVE
CVE-2026-40253
Published
Apr 16, 2026
Updated
Apr 16, 2026
Vendor
openCryptoki
Product
openCryptoki
Classifications
CWE-125
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 16, 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=<= 3.26.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

openCryptoki · openCryptokiversion=<= 3.26.0

Published CVSS scores

6.8GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
6.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/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.

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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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read

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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