Affected: OpenSSL, Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Issue summary: A type confusion vulnerability exists in the TimeStamp Response verification code where an ASN1_TYPE union member is accessed without first validating the type, causing an invalid or NULL pointer dereference when processing a malformed TimeStamp Response file.

Impact summary: An application calling TS_RESP_verify_response() with a malformed TimeStamp Response can be caused to dereference an invalid or NULL pointer when reading, resulting in a Denial of Service.

The functions ossl_ess_get_signing_cert() and ossl_ess_get_signing_cert_v2() access the signing cert attribute value without validating its type. When the type is not V_ASN1_SEQUENCE, this results in accessing invalid memory through the ASN1_TYPE union, causing a crash.

Exploiting this vulnerability requires an attacker to provide a malformed TimeStamp Response to an application that verifies timestamp responses. The TimeStamp protocol (RFC 3161) is not widely used and the impact of the exploit is just a Denial of Service. For these reasons the issue was assessed as Low severity.

The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the TimeStamp Response implementation is outside the OpenSSL FIPS module boundary.

OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue.

OpenSSL 1.0.2 is not affected by this issue.

Affected: Ubuntu:22.04:LTS: openssl, Ubuntu:24.04:LTS: openssl, Ubuntu:25.10: openssl

Stanislav Fort, Petr Šimeček, and Hamza discovered that OpenSSL incorrectly validated PBMAC1 parameters when doing PKCS#12 MAC verification. An attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. This issue only affected Ubuntu 25.10. (CVE-2025-11187)

Stanislav Fort discovered that OpenSSL incorrectly parsed CMS AuthEnvelopedData messages. An attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. (CVE-2025-15467)

Stanislav Fort discovered that OpenSSL incorrectly handled memory in the SSL_CIPHER_find() function. An attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. This issue only affected Ubuntu 25.10. (CVE-2025-15468)

Stanislav Fort discovered that the OpenSSL "openssl dgst" command line tool incorrectly truncated data to 16MB. An attacker could posibly use this issue to hide unauthenticated data beyond the 16MB limit. This issue only affected Ubuntu 25.10. (CVE-2025-15469)

Tomas Dulka and Stanislav Fort discovered that OpenSSL incorrectly handled memory with TLS 1.3 connections using certificate compression. An attacker could possibly use this issue to consume resources, leading to a denial of service. This issue only affected Ubuntu 25.10. (CVE-2025-66199)

Petr Simecek and Stanislav Fort discovered that OpenSSL incorrectly handled memory when writing large data into a BIO chain. An attacker could possibly use this issue to con…