A signal handler in sshd(8) may call a logging function that is not async-signal-safe. The signal handler is invoked when a client does not authenticate within the LoginGraceTime seconds (120 by default). This signal handler executes in the context of the sshd(8)'s privileged code, which is not sandboxed and runs with full root privileges. This issue is another instance of the problem in CVE-2024-6387 addressed by FreeBSD-SA-24:04.openssh. The faulty code in this case is from the integration of blacklistd in OpenSSH in FreeBSD. As a result of calling functions that are not async-signal-safe in the privileged sshd(8) context, a race condition exists that a determined attacker may be able to exploit to allow an unauthenticated remote code execution as root.

A logic bug in the code which disables kernel tracing for setuid programs meant that tracing was not disabled when it should have, allowing unprivileged users to trace and inspect the behavior of setuid programs. The bug may be used by an unprivileged user to read the contents of files to which they would not otherwise have access, such as the local password database.

When mounting a remote filesystem using NFS, the kernel did not sanitize remotely provided filenames for the path separator character, "/". This allows readdir(3) and related functions to return filesystem entries with names containing additional path components. The lack of validation described above gives rise to a confused deputy problem. For example, a program copying files from an NFS mount could be tricked into copying from outside the intended source directory, and/or to a location outside the intended destination directory.

The e1000 network adapters permit a variety of modifications to an Ethernet packet when it is being transmitted. These include the insertion of IP and TCP checksums, insertion of an Ethernet VLAN header, and TCP segmentation offload ("TSO"). The e1000 device model uses an on-stack buffer to generate the modified packet header when simulating these modifications on transmitted packets. When checksum offload is requested for a transmitted packet, the e1000 device model used a guest-provided value to specify the checksum offset in the on-stack buffer. The offset was not validated for certain packet types. A misbehaving bhyve guest could overwrite memory in the bhyve process on the host, possibly leading to code execution in the host context. The bhyve process runs in a Capsicum sandbox, which (depending on the FreeBSD version and bhyve configuration) limits the impact of exploiting this issue.

Handlers for *_CFG_PAGE read / write ioctls in the mpr, mps, and mpt drivers allocated a buffer of a caller-specified size, but copied to it a fixed size header. Other heap content would be overwritten if the specified size was too small. Users with access to the mpr, mps or mpt device node may overwrite heap data, potentially resulting in privilege escalation. Note that the device node is only accessible to root and members of the operator group.

A user-provided integer option was passed to nmreq_copyin() without checking if it would overflow. This insufficient bounds checking could lead to kernel memory corruption. On systems configured to include netmap in their devfs_ruleset, a privileged process running in a jail can affect the host environment.

The total size of the user-provided nmreq to nmreq_copyin() was first computed and then trusted during the copyin. This time-of-check to time-of-use bug could lead to kernel memory corruption. On systems configured to include netmap in their devfs_ruleset, a privileged process running in a jail can affect the host environment.

The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from the extension negotiation message), and a client and server may consequently end up with a connection for which some security features have been downgraded or disabled, aka a Terrapin attack. This occurs because the SSH Binary Packet Protocol (BPP), implemented by these extensions, mishandles the handshake phase and mishandles use of sequence numbers. For example, there is an effective attack against SSH's use of ChaCha20-Poly1305 (and CBC with Encrypt-then-MAC). The bypass occurs in chacha20-poly1305@openssh.com and (if CBC is used) the -etm@openssh.com MAC algorithms. This also affects Maverick Synergy Java SSH API before 3.1.0-SNAPSHOT, Dropbear through 2022.83, Ssh before 5.1.1 in Erlang/OTP, PuTTY before 0.80, AsyncSSH before 2.14.2, golang.org/x/crypto before 0.17.0, libssh before 0.10.6, libssh2 through 1.11.0, Thorn Tech SFTP Gateway before 3.4.6, Tera Term before 5.1, Paramiko before 3.4.0, jsch before 0.2.15, SFTPGo before 2.5.6, Netgate pfSense Plus through 23.09.1, Netgate pfSense CE through 2.7.2, HPN-SSH through 18.2.0, ProFTPD before 1.3.8b (and before 1.3.9rc2), ORYX CycloneSSH before 2.3.4, NetSarang XShell 7 before Build 0144, CrushFTP before 10.6.0, ConnectBot SSH library before 2.2.22, Apache MINA sshd through 2.11.0, sshj through 0.37.0, TinySSH through 20230101, trilead-ssh2 6401, LANCOM LCOS and LANconfig, FileZilla before 3.66.4, Nova before 11.8, PKIX-SSH before 14.4, SecureCRT before 9.4.3, Transmit5 before 5.10.4, Win32-OpenSSH before 9.5.0.0p1-Beta, WinSCP before 6.2.2, Bitvise SSH Server before 9.32, Bitvise SSH Client before 9.33, KiTTY through 0.76.1.13, the net-ssh gem 7.2.0 for Ruby, the mscdex ssh2 module before 1.15.0 for Node.js, the thrussh library before 0.35.1 for Rust, and the Russh crate before 0.40.2 for Rust.

In versions of FreeBSD 12.4-RELEASE prior to 12.4-RELEASE-p7 and FreeBSD 13.2-RELEASE prior to 13.2-RELEASE-p5 the __sflush() stdio function in libc does not correctly update FILE objects' write space members for write-buffered streams when the write(2) system call returns an error.  Depending on the nature of an application that calls libc's stdio functions and the presence of errors returned from the write(2) system call (or an overridden stdio write routine) a heap buffer overflow may occur. Such overflows may lead to data corruption or the execution of arbitrary code at the privilege level of the calling program.

On an msdosfs filesystem, the 'truncate' or 'ftruncate' system calls under certain circumstances populate the additional space in the file with unallocated data from the underlying disk device, rather than zero bytes. This may permit a user with write access to files on a msdosfs filesystem to read unintended data (e.g. from a previously deleted file).

In pf packet processing with a 'scrub fragment reassemble' rule, a packet containing multiple IPv6 fragment headers would be reassembled, and then immediately processed. That is, a packet with multiple fragment extension headers would not be recognized as the correct ultimate payload. Instead a packet with multiple IPv6 fragment headers would unexpectedly be interpreted as a fragmented packet, rather than as whatever the real payload is. As a result, IPv6 fragments may bypass pf firewall rules written on the assumption all fragments have been reassembled and, as a result, be forwarded or processed by the host.

pam_krb5 authenticates a user by essentially running kinit with the password, getting a ticket-granting ticket (tgt) from the Kerberos KDC (Key Distribution Center) over the network, as a way to verify the password. However, if a keytab is not provisioned on the system, pam_krb5 has no way to validate the response from the KDC, and essentially trusts the tgt provided over the network as being valid. In a non-default FreeBSD installation that leverages pam_krb5 for authentication and does not have a keytab provisioned, an attacker that is able to control both the password and the KDC responses can return a valid tgt, allowing authentication to occur for any user on the system.

When GELI reads a key file from standard input, it does not reuse the key file to initialize multiple providers at once resulting in the second and subsequent devices silently using a NULL key as the user key file. If a user only uses a key file without a user passphrase, the master key is encrypted with an empty key file allowing trivial recovery of the master key.

grub2-bhyve, as used in FreeBSD bhyve before revision 525916 2020-02-12, mishandles font loading by a guest through a grub2.cfg file, leading to a buffer overflow.

grub2-bhyve, as used in FreeBSD bhyve before revision 525916 2020-02-12, does not validate the address provided as part of a memrw command (read_* or write_*) by a guest through a grub2.cfg file. This allows an untrusted guest to perform arbitrary read or write operations in the context of the grub-bhyve process, resulting in code execution as root on the host OS.

Wi-Fi Protected Access (WPA and WPA2) that support 802.11v allows reinstallation of the Integrity Group Temporal Key (IGTK) when processing a Wireless Network Management (WNM) Sleep Mode Response frame, allowing an attacker within radio range to replay frames from access points to clients.

Wi-Fi Protected Access (WPA and WPA2) that support 802.11v allows reinstallation of the Group Temporal Key (GTK) when processing a Wireless Network Management (WNM) Sleep Mode Response frame, allowing an attacker within radio range to replay frames from access points to clients.

Wi-Fi Protected Access (WPA and WPA2) allows reinstallation of the Tunneled Direct-Link Setup (TDLS) Peer Key (TPK) during the TDLS handshake, allowing an attacker within radio range to replay, decrypt, or spoof frames.

Wi-Fi Protected Access (WPA and WPA2) allows reinstallation of the Station-To-Station-Link (STSL) Transient Key (STK) during the PeerKey handshake, allowing an attacker within radio range to replay, decrypt, or spoof frames.

Wi-Fi Protected Access (WPA and WPA2) that supports IEEE 802.11r allows reinstallation of the Pairwise Transient Key (PTK) Temporal Key (TK) during the fast BSS transmission (FT) handshake, allowing an attacker within radio range to replay, decrypt, or spoof frames.