CVE-2026-34181

CVE-2026-34181 · PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 7.4 · High · EPSS 0.2% · Fix available

Published

2026-06-09T16:03:22.065Z

Updated

2026-06-10T16:02:19.675Z

Stack: system · network

Check your server →