CVE-2020-14145

The client side in OpenSSH 5.7 through 8.4 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client). NOTE: some reports st...

CVE-2019-6111

An issue was discovered in OpenSSH 7.9. Due to the scp implementation being derived from 1983 rcp, the server chooses which files/directories are sent to the client. However, the scp client only performs cursory validation of the object name returned (only directory traversal attacks are prevented)...

CVE-2018-15919

Remotely observable behaviour in auth-gss2.c in OpenSSH through 7.8 could be used by remote attackers to detect existence of users on a target system when GSS2 is in use. NOTE: the discoverer states 'We understand that the OpenSSH developers do not want to treat such a username enumeration (or "ora...

CVE-2017-15906

The process_open function in sftp-server.c in OpenSSH before 7.6 does not properly prevent write operations in readonly mode, which allows attackers to create zero-length files.

CVE-2016-20012

OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: ...

CVE-2018-20685

In OpenSSH 7.9, scp.c in the scp client allows remote SSH servers to bypass intended access restrictions via the filename of . or an empty filename. The impact is modifying the permissions of the target directory on the client side.

CVE-2018-15473

OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c.

CVE-2010-5107

The default configuration of OpenSSH through 6.1 enforces a fixed time limit between establishing a TCP connection and completing a login, which makes it easier for remote attackers to cause a denial of service (connection-slot exhaustion) by periodically making many new TCP connections.

CVE-2023-48795

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 connecti...

CVE-2016-6210

sshd in OpenSSH before 7.3, when SHA256 or SHA512 are used for user password hashing, uses BLOWFISH hashing on a static password when the username does not exist, which allows remote attackers to enumerate users by leveraging the timing difference between responses when a large password is provided...

CVE-2023-51384

In ssh-agent in OpenSSH before 9.6, certain destination constraints can be incompletely applied. When destination constraints are specified during addition of PKCS#11-hosted private keys, these constraints are only applied to the first key, even if a PKCS#11 token returns multiple keys.

CVE-2016-10011

authfile.c in sshd in OpenSSH before 7.4 does not properly consider the effects of realloc on buffer contents, which might allow local users to obtain sensitive private-key information by leveraging access to a privilege-separated child process.

CVE-2007-2243

OpenSSH 4.6 and earlier, when ChallengeResponseAuthentication is enabled, allows remote attackers to determine the existence of user accounts by attempting to authenticate via S/KEY, which displays a different response if the user account exists, a similar issue to CVE-2001-1483.

CVE-2014-2653

The verify_host_key function in sshconnect.c in the client in OpenSSH 6.6 and earlier allows remote servers to trigger the skipping of SSHFP DNS RR checking by presenting an unacceptable HostCertificate.

CVE-2025-26466

A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A malicious client may keep sending such packages, leading to an...

CVE-2014-2532

sshd in OpenSSH before 6.6 does not properly support wildcards on AcceptEnv lines in sshd_config, which allows remote attackers to bypass intended environment restrictions by using a substring located before a wildcard character.

CVE-2006-5052

Unspecified vulnerability in portable OpenSSH before 4.4, when running on some platforms, allows remote attackers to determine the validity of usernames via unknown vectors involving a GSSAPI "authentication abort."

CVE-2008-4109

A certain Debian patch for OpenSSH before 4.3p2-9etch3 on etch; before 4.6p1-1 on sid and lenny; and on other distributions such as SUSE uses functions that are not async-signal-safe in the signal handler for login timeouts, which allows remote attackers to cause a denial of service (connection slo...

CVE-2016-1907

The ssh_packet_read_poll2 function in packet.c in OpenSSH before 7.1p2 allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via crafted network traffic.

CVE-2003-0190

OpenSSH-portable (OpenSSH) 3.6.1p1 and earlier with PAM support enabled immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.

CVE-2005-2798

sshd in OpenSSH before 4.2, when GSSAPIDelegateCredentials is enabled, allows GSSAPI credentials to be delegated to clients who log in using non-GSSAPI methods, which could cause those credentials to be exposed to untrusted users or hosts.

CVE-2011-0539

The key_certify function in usr.bin/ssh/key.c in OpenSSH 5.6 and 5.7, when generating legacy certificates using the -t command-line option in ssh-keygen, does not initialize the nonce field, which might allow remote attackers to obtain sensitive stack memory contents or make it easier to conduct ha...

CVE-2006-0883

OpenSSH on FreeBSD 5.3 and 5.4, when used with OpenPAM, does not properly handle when a forked child process terminates during PAM authentication, which allows remote attackers to cause a denial of service (client connection refusal) by connecting multiple times to the SSH server, waiting for the p...

CVE-2004-2069

sshd.c in OpenSSH 3.6.1p2 and 3.7.1p2 and possibly other versions, when using privilege separation, does not properly signal the non-privileged process when a session has been terminated after exceeding the LoginGraceTime setting, which leaves the connection open and allows remote attackers to caus...

CVE-2006-4925

packet.c in ssh in OpenSSH allows remote attackers to cause a denial of service (crash) by sending an invalid protocol sequence with USERAUTH_SUCCESS before NEWKEYS, which causes newkeys[mode] to be NULL.

CVE-2001-1382

The "echo simulation" traffic analysis countermeasure in OpenSSH before 2.9.9p2 sends an additional echo packet after the password and carriage return is entered, which could allow remote attackers to determine that the countermeasure is being used.

CVE-2000-0217

The default configuration of SSH allows X forwarding, which could allow a remote attacker to control a client's X sessions via a malicious xauth program.

CVE-2000-0992

Directory traversal vulnerability in scp in sshd 1.2.xx allows a remote malicious scp server to overwrite arbitrary files via a .. (dot dot) attack.

CVE-2005-2797

OpenSSH 4.0, and other versions before 4.2, does not properly handle dynamic port forwarding ("-D" option) when a listen address is not provided, which may cause OpenSSH to enable the GatewayPorts functionality.

CVE-2007-4654

Unspecified vulnerability in SSHield 1.6.1 with OpenSSH 3.0.2p1 on Cisco WebNS 8.20.0.1 on Cisco Content Services Switch (CSS) series 11000 devices allows remote attackers to cause a denial of service (connection slot exhaustion and device crash) via a series of large packets designed to exploit th...