Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.

Jonathan Looney discovered that the TCP retransmission queue implementation in tcp_fragment in the Linux kernel could be fragmented when handling certain TCP Selective Acknowledgment (SACK) sequences. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commit f070ef2ac66716357066b683fb0baf55f8191a2e.

Jonathan Looney discovered that the TCP_SKB_CB(skb)->tcp_gso_segs value was subject to an integer overflow in the Linux kernel when handling TCP Selective Acknowledgments (SACKs). A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commit 3b4929f65b0d8249f19a50245cd88ed1a2f78cff.

On BIG-IP 14.0.0-14.1.0.1, 13.0.0-13.1.1.4, 12.1.0-12.1.4, 11.6.1-11.6.3.4, and 11.5.2-11.5.8, users with the Resource Administrator role can modify sensitive portions of the filesystem if provided Advanced Shell Access, such as editing /etc/passwd. This allows modifications to user objects and is contrary to our definition for the Resource Administrator (RA) role restrictions.

On BIG-IP 14.0.0-14.1.0.1, 13.0.0-13.1.1.4, 12.1.0-12.1.4, 11.6.1-11.6.3.4, and 11.5.2-11.5.8, a user with the Resource Administrator role is able to overwrite sensitive low-level files (such as /etc/passwd) using SFTP to modify user permissions, without Advanced Shell access. This is contrary to our definition for the Resource Administrator (RA) role restrictions.

On BIG-IP 14.0.0-14.1.0.1, 13.0.0-13.1.1.4, 12.1.0-12.1.4, 11.6.1-11.6.3.4, and 11.5.2-11.5.8, administrative users with TMSH access can overwrite critical system files on BIG-IP which can result in bypass of whitelist / blacklist restrictions enforced by appliance mode.

On BIG-IP 14.0.0-14.1.0.1, 13.0.0-13.1.1.4, 12.1.0-12.1.4, 11.6.1-11.6.3.4, and 11.5.2-11.5.8, Administrator and Resource Administrator roles might exploit TMSH access to bypass Appliance Mode restrictions on BIG-IP systems.

On BIG-IP 13.0.0-13.1.1.4, 12.1.0-12.1.4, 11.6.1-11.6.3.4, and 11.5.2-11.5.8, SNMP may expose sensitive configuration objects over insecure transmission channels. This issue is exposed when a passphrase is used with various profile types and is accessed using SNMPv2.

When BIG-IP 14.0.0-14.1.0.1, 13.0.0-13.1.1.4, 12.1.0-12.1.4, 11.6.1-11.6.3.4, and 11.5.2-11.5.8 are processing certain rare data sequences occurring in PPTP VPN traffic, the BIG-IP system may execute incorrect logic. The TMM may restart and produce a core file as a result of this condition. The BIG-IP system provisioned with the CGNAT module and configured with a virtual server using a PPTP profile is exposed to this vulnerability.

On BIG-IP 11.5.1-11.6.3.4, 12.1.0-12.1.3.7, 13.0.0-13.1.1.3, and 14.0.0-14.0.0.2, when processing certain SNMP requests with a request-id of 0, the snmpd process may leak a small amount of memory.

On BIG-IP 11.5.1-11.5.8, 11.6.1-11.6.3, and 12.0.x, an undisclosed sequence of packets received by an SSL virtual server and processed by an associated Client SSL or Server SSL profile may cause a denial of service.

The Linux kernel, versions 3.9+, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly. An attacker may cause a denial of service condition by sending specially crafted IP fragments. Various vulnerabilities in IP fragmentation have been discovered and fixed over the years. The current vulnerability (CVE-2018-5391) became exploitable in the Linux kernel with the increase of the IP fragment reassembly queue size.

racoon/gssapi.c in IPsec-Tools 0.8.2 allows remote attackers to cause a denial of service (NULL pointer dereference and IKE daemon crash) via a series of crafted UDP requests.