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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HFreebsd
OSFreebsd13.314.014.1< 13.013.1 – 13.3 (excl.)
Related vulnerabilities
The ISO-2022 encoding module used a stack buffer sized to MB_LEN_MAX (6 bytes) for intermediate character outp...
Several encoding modules, including HZ, UTF-7, VIQR, and ZW, did not properly check the size of the caller-sup...
FreeBSD UMTX_SHM_DESTROY: use-after-free umożliwiający RCE lub ucieczkę z sandboxa
RCE w implementacji NFS w OpenBSD i FreeBSD — zdalne wykonanie kodu
FreeBSD: przepełnienie bufora w obsłudze beacon 802.11s prowadzące do RCE