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CVE-2026-63076 on CTRL-OS 26.05

Aliases: CVE-2026-63076

Packages: openssl_3, openssl_3_5, openssl_3_6, openssl_4_0

Status: Plausible

Advisory Information

Issue summary: OpenSSL CMP password based protection verification only checks whether the protectionAlg parameter was not NULL and not its ASN.1 type, before treating it as a PBMParameter. A crafted message can contain a parameter of a different type, which is then dereferenced as an invalid pointer.

Impact summary: A remote, unauthenticated attacker can crash an application acting as a CMP server that accepts PBM-protected messages, or a CMP client talking to a malicious or intercepted CMP server, resulting in a Denial of Service.

CWE: CWE-476: NULL Pointer Dereference

Description: When verifying the password-based MAC protection of a CMP message, OpenSSL library reads the protectionAlg algorithm parameter with X509_ALGOR_get0(), which returns both the parameter type and its value pointer. The value is then cast to an ASN1_STRING and treated as the expected PBMParameter after only checking that pointer is not NULL. The parameter type returned by X509_ALGOR_get0() was never consulted.

This happens during protection verification, before any MAC is computed, so no knowledge of the PBM shared secret is required; the only precondition is that PBM verification is reachable. On the server side this is reached from OSSL_CMP_SRV_process_request() for any application that stands up a CMP server accepting PBM-protected messages, and on the client side from CMP response validation against a malicious or on-path (MITM) server. The reliable consequence is a denial of service; there is no memory disclosure, no controlled memory write, and no path to code execution. CMP is a specialized feature that an application must explicitly enable.

FIPS impact: no As the CMP code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.

Updates

2026-08-25 17:38 CEST

Metadata changes:

  • Status for package openssl_3: “Plausible”
  • Status for package openssl_3_5: “Plausible”
  • Status for package openssl_3_6: “Plausible”
  • Status for package openssl_4_0: “Plausible”

2026-08-25 17:36 CEST

Metadata changes:

  • Status for package openssl_3: “New”
  • Status for package openssl_3_5: “New”
  • Status for package openssl_3_6: “New”
  • Status for package openssl_4_0: “New”