Title: OpenSSL, Description: Resumen del problema: El procesamiento de archivos PKCS#12 no realiza una validación de entrada suficiente para archivos que utilizan el mecanismo de integridad Password-Based Message Authentication Code 1 (PBMAC1), lo que permite la falsificación de un certificado y una clave privada.

Resumen del impacto: Un atacante suplantando a un usuario puede hacer que un servicio que lee archivos PKCS#12 acepte certificados y claves privadas falsificados con una probabilidad de 1 entre 256.

Si un servicio que acepta archivos PKCS#12 está utilizando contraseñas para la autenticación de los archivos recibidos, el atacante puede crear archivos PKCS#12 sin cifrar que utilizan autenticación PBMAC1 que especifica una clave HMAC de solo un byte, permitiéndoles crear un archivo que será aceptado con una probabilidad de 1 entre 256. Eso entonces haría que el servicio acepte un certificado y una clave privada controlados por el atacante.

Los módulos FIPS no se ven afectados por este problema, ya que el código afectado está fuera del límite del módulo FIPS de OpenSSL.

{"timestamp":"2026-06-10T16:01:11.685759Z","id":"CVE-2026-34181","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}

[{"vendor":"OpenSSL","product":"OpenSSL","defaultStatus":"unaffected","versions":[{"version":"4.0.0","lessThan":"4.0.1","versionType":"semver","status":"affected"},{"version":"3.6.0","lessThan":"3.6.3","versionType":"semver","status":"affected"},{"version":"3.5.0","lessThan":"3.5.7","versionType":"semver","status":"affected"},{"version":"3.4.0","lessThan":"3.4.6","versionType":"semver","status":"affected"}]}]

OR
          *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 3.4.0 up to (excluding) 3.4.6
          *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 3.5.0 up to (excluding) 3.5.7
          *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 3.6.0 up to (excluding) 3.6.3
          *cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:*

OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/0300eb9ddce7a0895bf301a4b0c03a9da2313a0f Types: Patch

OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/79eb76a937e474bb7610a0a3dc57131dc8dc6610 Types: Patch

OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/85dcbb3abaa4878af5c8fbbe11bce708fcf984a7 Types: Patch

OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/ec36f2417c4ddd8cabce4b4a60a3d7a7365f2d81 Types: Patch

OpenSSL Software Foundation: https://openssl-library.org/news/secadv/20260609.txt Types: Vendor Advisory

AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

https://github.com/openssl/openssl/commit/0300eb9ddce7a0895bf301a4b0c03a9da2313a0f

https://github.com/openssl/openssl/commit/79eb76a937e474bb7610a0a3dc57131dc8dc6610

https://github.com/openssl/openssl/commit/85dcbb3abaa4878af5c8fbbe11bce708fcf984a7

https://github.com/openssl/openssl/commit/ec36f2417c4ddd8cabce4b4a60a3d7a7365f2d81

https://github.com/openssl/security/commit/0300eb9ddce7a0895bf301a4b0c03a9da2313a0f

https://github.com/openssl/security/commit/79eb76a937e474bb7610a0a3dc57131dc8dc6610

https://github.com/openssl/security/commit/85dcbb3abaa4878af5c8fbbe11bce708fcf984a7

https://github.com/openssl/security/commit/ec36f2417c4ddd8cabce4b4a60a3d7a7365f2d81

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.

CWE-354

https://github.com/openssl/security/commit/0300eb9ddce7a0895bf301a4b0c03a9da2313a0f

https://github.com/openssl/security/commit/79eb76a937e474bb7610a0a3dc57131dc8dc6610

https://github.com/openssl/security/commit/85dcbb3abaa4878af5c8fbbe11bce708fcf984a7

https://github.com/openssl/security/commit/ec36f2417c4ddd8cabce4b4a60a3d7a7365f2d81

https://openssl-library.org/news/secadv/20260609.txt