CVE-2026-34181

/// Technical 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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References