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.
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

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