Affected devices contain a vulnerability that allows an unauthenticated attacker to trigger a denial of service condition. The vulnerability can be triggered if a large amount of DCP reset packets are sent to the device.

Profinet-IO (PNIO) stack versions prior V06.00 do not properly limit internal resource allocation when multiple legitimate diagnostic package requests are sent to the DCE-RPC interface. This could lead to a denial of service condition due to lack of memory for devices that include a vulnerable version of the stack.

The security vulnerability could be exploited by an attacker with network access to an affected device. Successful exploitation requires no system privileges and no user interaction. An attacker could use the vulnerability to compromise the availability of the device.

An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signaturealgorithms extension (where it was present in the initial ClientHello), but includes a signaturealgorithmscert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack. A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS clients are not impacted by this issue. All OpenSSL 1.1.1 versions are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1-1.1.1j).