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 signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert 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).

The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a "purpose" has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named "purpose" values implemented in libcrypto perform this check. Therefore, where a purpose is set the certificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verific…

In FreeBSD before 11.1-STABLE, 11.2-RELEASE-p2, 11.1-RELEASE-p13, ip fragment reassembly code is vulnerable to a denial of service due to excessive system resource consumption. This issue can allow a remote attacker who is able to send an arbitrary ip fragments to cause the machine to consume excessive resources.

Integer overflow in the _gd2GetHeader function in gd_gd2.c in the GD Graphics Library (aka libgd) before 2.2.3, as used in PHP before 5.5.37, 5.6.x before 5.6.23, and 7.x before 7.0.8, allows remote attackers to cause a denial of service (heap-based buffer overflow and application crash) or possibly have unspecified other impact via crafted chunk dimensions in an image.

Integer overflow in FreeBSD before 8.4 p24, 9.x before 9.3 p10. 10.0 before p18, and 10.1 before p6 allows remote attackers to cause a denial of service (crash) via a crafted IGMP packet, which triggers an incorrect size calculation and allocation of insufficient memory.

FreeBSD 9.1, 9.2, and 10.0, when compiling OpenSSH with Kerberos support, uses incorrect library ordering when linking sshd, which causes symbols to be resolved incorrectly and allows remote attackers to cause a denial of service (sshd deadlock and prevention of new connections) by ending multiple connections before authentication is completed.

The setlogin function in FreeBSD 8.4 through 10.1-RC4 does not initialize the buffer used to store the login name, which allows local users to obtain sensitive information from kernel memory via a call to getlogin, which returns the entire buffer.

namei in FreeBSD 9.1 through 10.1-RC2 allows remote attackers to cause a denial of service (memory exhaustion) via vectors that trigger a sandboxed process to look up a large number of nonexistent path names.

routed in FreeBSD 8.4 through 10.1-RC2 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via an RIP request from a source not on a directly connected network.

Stack-based buffer overflow in rtsold in FreeBSD 9.1 through 10.1-RC2 allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via crafted DNS parameters in a router advertisement message.