Issue Summary: The PKCS#12 file processing fails to perform sufficient input
validation for files that use Password-Based Message Authentication Code 1
(PBMAC1) integrity mechanism allowing a certificate and private key forgery.

Impact Summary: An attacker impersonating a user can cause a service reading
PKCS#12 files to accept forged certificates and private keys with a 1 in 256
probability.

If a service accepting PKCS#12 files is using passwords for authenticating
the received files, the attacker can create unencrypted PKCS#12 files that
use PBMAC1 authentication that specifies an HMAC key of only one byte, allowing
them to craft a file that will be accepted with a 1 in 256 probability.
That would then cause the service to accept a certificate and private key
controlled by the attacker.

The FIPS modules are not affected by this issue, as the affected code is
outside the OpenSSL FIPS module boundary.

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Solution

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History

Tue, 09 Jun 2026 16:30:00 +0000

Type Values Removed Values Added
Description Issue Summary: The PKCS#12 file processing fails to perform sufficient input validation for files that use Password-Based Message Authentication Code 1 (PBMAC1) integrity mechanism allowing a certificate and private key forgery. Impact Summary: An attacker impersonating a user can cause a service reading PKCS#12 files to accept forged certificates and private keys with a 1 in 256 probability. If a service accepting PKCS#12 files is using passwords for authenticating the received files, the attacker can create unencrypted PKCS#12 files that use PBMAC1 authentication that specifies an HMAC key of only one byte, allowing them to craft a file that will be accepted with a 1 in 256 probability. That would then cause the service to accept a certificate and private key controlled by the attacker. The FIPS modules are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.
Title PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys
Weaknesses CWE-354
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: openssl

Published:

Updated: 2026-06-09T16:03:22.065Z

Reserved: 2026-03-26T09:29:36.013Z

Link: CVE-2026-34181

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-06-09T17:17:04.740

Modified: 2026-06-09T17:17:04.740

Link: CVE-2026-34181

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-09T17:30:10Z

Weaknesses