Out-of-Bounds write in systemd-networkd dhcpv6 option handling

A buffer overflow vulnerability in the dhcp6 client of systemd allows a malicious dhcp6 server to overwrite heap memory in systemd-networkd. Affected releases are systemd: versions up to and including 239.

systemd: chown_one() can dereference symlinks

A race condition in chown_one() of systemd allows an attacker to cause systemd to set arbitrary permissions on arbitrary files. Affected releases are systemd versions up to and including 239.

systemd: reexec state injection: fgets() on overlong lines leads to line splitting

A vulnerability in unit_deserialize of systemd allows an attacker to supply arbitrary state across systemd re-execution via NotifyAccess. This can be used to improperly influence systemd execution and possibly lead to root privilege escalation. Affected releases are systemd versions up to and including 239.

systemd: TOCTOU race condition when updating file permissions and SELinux security contexts

systemd, when updating file permissions, allows local users to change the permissions and SELinux security contexts for arbitrary files via a symlink attack on unspecified files.

systemd: stack overflow when calling syslog from a command with long cmdline

An allocation of memory without limits, that could result in the stack clashing with another memory region, was discovered in systemd-journald when a program with long command line arguments calls syslog. A local attacker may use this flaw to crash systemd-journald or escalate his privileges. Versions through v240 are vulnerable.

systemd: stack overflow when receiving many journald entries

An allocation of memory without limits, that could result in the stack clashing with another memory region, was discovered in systemd-journald when many entries are sent to the journal socket. A local attacker, or a remote one if systemd-journal-remote is used, may use this flaw to crash systemd-journald or execute code with journald privileges. Versions through v240 are vulnerable.

systemd: services with DynamicUser can create SUID/SGID binaries

It was discovered that a systemd service that uses DynamicUser property can create a SUID/SGID binary that would be allowed to run as the transient service UID/GID even after the service is terminated. A local attacker may use this flaw to access resources that will be owned by a potentially different service in the future, when the UID/GID will be recycled.

systemd: services with DynamicUser can get new privileges and create SGID binaries

It was discovered that a systemd service that uses DynamicUser property can get new privileges through the execution of SUID binaries, which would allow to create binaries owned by the service transient group with the setgid bit set. A local attacker may use this flaw to access resources that will be owned by a potentially different service in the future, when the GID will be recycled.

systemd: Spoofing of XDG_SEAT allows for actions to be checked against "allow_active" instead of "allow_any"

In systemd before v242-rc4, it was discovered that pam_systemd does not properly sanitize the environment before using the XDG_SEAT variable. It is possible for an attacker, in some particular configurations, to set a XDG_SEAT environment variable which allows for commands to be checked against polkit policies using the "allow_active" element rather than "allow_any".

systemd: out-of-bounds read when parsing a crafted syslog message

An out of bounds read was discovered in systemd-journald in the way it parses log messages that terminate with a colon ':'. A local attacker can use this flaw to disclose process memory data. Versions from v221 to v239 are vulnerable.

systemd: mishandling of the current keyboard mode check leading to passwords being disclosed in cleartext to attacker

systemd 242 changes the VT1 mode upon a logout, which allows attackers to read cleartext passwords in certain circumstances, such as watching a shutdown, or using Ctrl-Alt-F1 and Ctrl-Alt-F2. This occurs because the KDGKBMODE (aka current keyboard mode) check is mishandled.

systemd: Infinite loop in the dns_packet_read_type_window() function

In systemd 223 through 235, a remote DNS server can respond with a custom crafted DNS NSEC resource record to trigger an infinite loop in the dns_packet_read_type_window() function of the 'systemd-resolved' service and cause a DoS of the affected service.

systemd: Stack overflow in nss-mymachines

Stack-based buffer overflow in the getpwnam and getgrnam functions of the NSS module nss-mymachines in systemd.

systemd: systemd creates world-writable suid files allowing root privilege escalation

A flaw in systemd v228 in /src/basic/fs-util.c caused world writable suid files to be created when using the systemd timers features, allowing local attackers to escalate their privileges to root. This is fixed in v229.

systemd: Out-of-bounds write in systemd-resolved due to allocating too small buffer in dns_packet_new

In systemd through 233, certain sizes passed to dns_packet_new in systemd-resolved can cause it to allocate a buffer that's too small. A malicious DNS server can exploit this via a response with a specially crafted TCP payload to trick systemd-resolved into allocating a buffer that's too small, and subsequently write arbitrary data beyond the end of it.

systemd: fails to parse usernames that start with digits

systemd v233 and earlier fails to safely parse usernames starting with a numeric digit (e.g. "0day"), running the service in question with root privileges rather than the user intended.

systemd: Null pointer dereference in dns_packet_is_reply_for function

systemd-resolved through 233 allows remote attackers to cause a denial of service (daemon crash) via a crafted DNS response with an empty question section.

systemd: Assertion failure when PID 1 receives a zero-length message over notify socket

The manager_invoke_notify_message function in systemd 231 and earlier allows local users to cause a denial of service (assertion failure and PID 1 hang) via a zero-length message received over a notify socket.

The session_link_x11_socket function in login/logind-session.c in systemd-logind in systemd, possibly 37 and earlier, allows local users to create or overwrite arbitrary files via a symlink attack on the X11 user directory in /run/user/.

systemd: freeze when PID 1 receives a zero-length message over notify socket

The manager_dispatch_notify_fd function in systemd allows local users to cause a denial of service (system hang) via a zero-length message received over a notify socket, which causes an error to be returned and the notification handler to be disabled.