Title: Double-free When Checking OCSP Stapled Response, Description: Resumen del problema: Un servidor malicioso puede explotar el 'TLS OCSP stapling' entregando una respuesta manipulada a través de la 'extension status_request', desencadenando un 'double-free' en la ruta de verificación de certificados del cliente.

Resumen del impacto: La explotación exitosa permite a un atacante corromper la memoria 'heap' a través de un 'double-free', lo que podría llevar a una denegación de servicio o posiblemente a una ejecución de código controlada por el atacante u otro comportamiento indefinido.

Si el 'OCSP stapling' está habilitado y el cliente TLS se conecta a un servidor malicioso, una respuesta 'OCSP stapled' manipulada puede desencadenar un 'double free' en el cliente TLS cuando se verifica la respuesta 'stapled'.

El 'OCSP stapling' no está habilitado por defecto. La ejecución de código fiable a través de un 'double-free' es técnicamente compleja y altamente dependiente del entorno, pero el impacto de denegación de servicio es sencillo de lograr, lo que justifica una severidad Moderada.

Ningún módulo FIPS se ve afectado por este problema, ya que el código afectado está fuera del límite del módulo FIPS de OpenSSL.

{"timestamp":"2026-06-10T03:59:37.106557Z","id":"CVE-2026-35188","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"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"}]}]

OR
          *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/131145d25659e8749a9ed1afb383484854cffb78 Types: Patch

OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/78d0154cffda03aaaac63a087cc523a6b35fa8fd Types: Patch

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

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

https://github.com/openssl/openssl/commit/131145d25659e8749a9ed1afb383484854cffb78

https://github.com/openssl/openssl/commit/78d0154cffda03aaaac63a087cc523a6b35fa8fd

https://github.com/openssl/security/commit/131145d25659e8749a9ed1afb383484854cffb78

https://github.com/openssl/security/commit/78d0154cffda03aaaac63a087cc523a6b35fa8fd

Issue summary: A malicious server can exploit TLS OCSP stapling by delivering
a crafted response through the status_request extension, triggering a
double-free in the client's certificate verification path.

Impact summary: Successful exploitation allows an attacker to corrupt heap
memory via a double-free, potentially leading to a Denial of Service or
possibly an attacker controlled code execution or other undefined behavior.

If OCSP stapling is enabled and the TLS client connects to a malicious server,
a crafted OCSP stapled response can trigger a double free in the TLS client
when the stapled response is checked.

The OCSP stapling is not enabled by default. Reliable code execution
through a double-free is technically complex and highly environment-dependent
but the Denial of Service impact is straightforward to achieve, warranting
Moderate severity.

No FIPS modules are affected by this issue as the affected code is outside
the OpenSSL FIPS module boundary.

CWE-415

https://github.com/openssl/security/commit/131145d25659e8749a9ed1afb383484854cffb78

https://github.com/openssl/security/commit/78d0154cffda03aaaac63a087cc523a6b35fa8fd

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