PT-2026-47830 · Openssl · Openssl

Alex Gaynor + 2 · Published 2026-06-09 · Updated 2026-06-09 · CVE-2026-34181

Mitre

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.

Weakness Enumeration

CWE-354

Related Identifiers

CVE-2026-34181

Affected Products

Openssl

References · 6

• https://github.com/openssl/security/commit/85dcbb3abaa4878af5c8fbbe11bce708fcf984a7 · Patch
• https://github.com/openssl/security/commit/0300eb9ddce7a0895bf301a4b0c03a9da2313a0f · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-34181 · Security Note
• https://github.com/openssl/security/commit/79eb76a937e474bb7610a0a3dc57131dc8dc6610 · Patch
• https://github.com/openssl/security/commit/ec36f2417c4ddd8cabce4b4a60a3d7a7365f2d81 · Patch
• https://openssl-library.org/news/secadv/20260609.txt · Vendor Advisory