CVE-2026-8721Network attack vector

Password entropy reduction via embedded NULL truncation

Published May 17, 2026 · Updated May 17, 2026

Improper null termination in Crypt::OpenSSL::PKCS12 1.94 and earlier allows attackers to reduce password entropy via embedded NULLs. Password arguments in PKCS12.xs pass through the default Perl typemap without their byte lengths, causing C or OpenSSL code to stop at the first NULL. Exploitation requires an affected application to supply a binary, KDF-derived, or HMAC-derived password containing a NULL; later bytes are silently ignored.

CVSS severity9.8
Critical
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper null termination in Crypt::OpenSSL::PKCS12 1.94 and earlier allows attackers to reduce password entropy via embedded NULLs. Password arguments in PKCS12.xs pass through the default Perl typemap without their byte lengths, causing C or OpenSSL code to stop at the first NULL. Exploitation requires an affected application to supply a binary, KDF-derived, or HMAC-derived password containing a NULL; later bytes are silently ignored.

The record

CVE
CVE-2026-8721
Published
May 17, 2026
Updated
May 17, 2026
Vendor
Jonas B. Nielsen
Product
Crypt::OpenSSL::PKCS12
Classifications
CWE-170
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 17, 2026CVE publishedPublication date reported by the CVE source.
  2. May 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <=1.94

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Jonas B. Nielsen · Crypt::OpenSSL::PKCS12version=0 <=1.94

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-170Improper Null Termination

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo