The TLS stack in Mono before 3.12.1 makes it easier for remote attackers to conduct cipher-downgrade attacks to EXPORT_RSA ciphers via craft

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• mono-project monobefore 3.12.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2015-2320The TLS stack in Mono before 3.12.1 allows remote attackers to have unspecified impact via vectors related to client-side SSLv2 fallback.
  40Plan
• CVE-2015-2318The TLS stack in Mono before 3.12.1 allows man-in-the-middle attackers to conduct message skipping attacks and consequently impersonate clie
  33Monitor
• CVE-2012-3543mono 2.10.x ASP.NET Web Form Hash collision DoS
  31Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) {2  // Left empty for the test environment3}

1val client = OkHttpClient.Builder()2  .certificatePinner(3    CertificatePinner.Builder()4      .add("api.sirius.example", "sha256/…")5      .build()6  ).build()

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.