Review reviewHigh

CVE-2026-34181

OpenSSL OpenSSL, openssl

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 ke...

CVSS: 7.4
EPSS: 0.24%
CISA KEV: Not listed
Published: 2026.06.10

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.24%

Technical severityCVSS 7.4

Vulnerability overview

Affected product and versions

Product: OpenSSL OpenSSL, openssl
Affected versions: >= 4.0.0 < 4.0.1, >= 3.6.0 < 3.6.3, >= 3.5.0 < 3.5.7, >= 3.4.0 < 3.4.6, 4.0.0
Fixed versions: 3.4.6, 3.5.7, 3.6.3

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that OpenSSL OpenSSL, openssl and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE: CWE-354