Debian Libssh vulnerabilities

CVE-2026-0968 [CRITICAL] CVE-2026-0968: libssh - A flaw was found in libssh in which a malicious SFTP (SSH File Transfer Protocol... A flaw was found in libssh in which a malicious SFTP (SSH File Transfer Protocol) server can exploit this by sending a malformed 'longname' field within an `SSH_FXP_NAME` message during a file listing operation. This missing null check can lead to reading beyond allocated memory on the heap. This can cause unexpected behavior or lead to a denial of service (DoS) du

CVE-2026-0966 [MEDIUM] CVE-2026-0966: libssh - The API function `ssh_get_hexa()` is vulnerable, when 0-lenght input is provided... The API function `ssh_get_hexa()` is vulnerable, when 0-lenght input is provided to this function. This function is used internally in `ssh_get_fingerprint_hash()` and `ssh_print_hexa()` (deprecated), which is vulnerable to the same input (length is provided by the calling application). The function is also used internally in the gssapi code for logging the OIDs rece

CVE-2026-0964 [MEDIUM] CVE-2026-0964: libssh - A malicious SCP server can send unexpected paths that could make the client appl... A malicious SCP server can send unexpected paths that could make the client application override local files outside of working directory. This could be misused to create malicious executable or configuration files and make the user execute them under specific consequences. This is the same issue as in OpenSSH, tracked as CVE-2019-6111. Scope: local bookworm: open bu

CVE-2026-3731 [MEDIUM] CVE-2026-3731: libssh - A weakness has been identified in libssh up to 0.11.3. The impacted element is t... A weakness has been identified in libssh up to 0.11.3. The impacted element is the function sftp_extensions_get_name/sftp_extensions_get_data of the file src/sftp.c of the component SFTP Extension Name Handler. Executing a manipulation of the argument idx can lead to out-of-bounds read. The attack may be performed from remote. Upgrading to version 0.11.4 and 0.12.0 i

CVE-2026-0967 [MEDIUM] CVE-2026-0967: libssh - A flaw was found in libssh. A remote attacker, by controlling client configurati... A flaw was found in libssh. A remote attacker, by controlling client configuration files or known_hosts files, could craft specific hostnames that when processed by the `match_pattern()` function can lead to inefficient regular expression backtracking. This can cause timeouts and resource exhaustion, resulting in a Denial of Service (DoS) for the client. Scope: local

CVE-2026-0965 [LOW] CVE-2026-0965: libssh - A flaw was found in libssh where it can attempt to open arbitrary files during c... A flaw was found in libssh where it can attempt to open arbitrary files during configuration parsing. A local attacker can exploit this by providing a malicious configuration file or when the system is misconfigured. This vulnerability could lead to a Denial of Service (DoS) by causing the system to try and access dangerous files, such as block devices or large system f

CVE-2025-5987 [HIGH] CVE-2025-5987: libssh - A flaw was found in libssh when using the ChaCha20 cipher with the OpenSSL libra... A flaw was found in libssh when using the ChaCha20 cipher with the OpenSSL library. If an attacker manages to exhaust the heap space, this error is not detected and may lead to libssh using a partially initialized cipher context. This occurs because the OpenSSL error code returned aliases with the SSH_OK code, resulting in libssh not properly detecting the error return

CVE-2025-5318 [HIGH] CVE-2025-5318: libssh - A flaw was found in the libssh library in versions less than 0.11.2. An out-of-b... A flaw was found in the libssh library in versions less than 0.11.2. An out-of-bounds read can be triggered in the sftp_handle function due to an incorrect comparison check that permits the function to access memory beyond the valid handle list and to return an invalid pointer, which is used in further processing. This vulnerability allows an authenticated remote attac

CVE-2025-8114 [MEDIUM] CVE-2025-8114: libssh - A flaw was found in libssh, a library that implements the SSH protocol. When cal... A flaw was found in libssh, a library that implements the SSH protocol. When calculating the session ID during the key exchange (KEX) process, an allocation failure in cryptographic functions may lead to a NULL pointer dereference. This issue can cause the client or server to crash. Scope: local bookworm: resolved (fixed in 0.10.6-0+deb12u2) bullseye: resolved (fixed

CVE-2025-4877 [MEDIUM] CVE-2025-4877: libssh - There's a vulnerability in the libssh package where when a libssh consumer passe... There's a vulnerability in the libssh package where when a libssh consumer passes in an unexpectedly large input buffer to ssh_get_fingerprint_hash() function. In such cases the bin_to_base64() function can experience an integer overflow leading to a memory under allocation, when that happens it's possible that the program perform out of bounds write leading to a hea

CVE-2025-5351 [MEDIUM] CVE-2025-5351: libssh - A flaw was found in the key export functionality of libssh. The issue occurs in ... A flaw was found in the key export functionality of libssh. The issue occurs in the internal function responsible for converting cryptographic keys into serialized formats. During error handling, a memory structure is freed but not cleared, leading to a potential double free issue if an additional failure occurs later in the function. This condition may result in hea

CVE-2025-5372 [MEDIUM] CVE-2025-5372: libssh - A flaw was found in libssh versions built with OpenSSL versions older than 3.0, ... A flaw was found in libssh versions built with OpenSSL versions older than 3.0, specifically in the ssh_kdf() function responsible for key derivation. Due to inconsistent interpretation of return values where OpenSSL uses 0 to indicate failure and libssh uses 0 for success—the function may mistakenly return a success status even when key derivation fails. This result

CVE-2025-4878 [LOW] CVE-2025-4878: libssh - A vulnerability was found in libssh, where an uninitialized variable exists unde... A vulnerability was found in libssh, where an uninitialized variable exists under certain conditions in the privatekey_from_file() function. This flaw can be triggered if the file specified by the filename doesn't exist and may lead to possible signing failures or heap corruption. Scope: local bookworm: resolved (fixed in 0.10.6-0+deb12u2) bullseye: resolved (fixed in 0

CVE-2025-8277 [LOW] CVE-2025-8277: libssh - A flaw was found in libssh's handling of key exchange (KEX) processes when a cli... A flaw was found in libssh's handling of key exchange (KEX) processes when a client repeatedly sends incorrect KEX guesses. The library fails to free memory during these rekey operations, which can gradually exhaust system memory. This issue can lead to crashes on the client side, particularly when using libgcrypt, which impacts application stability and availability. S

CVE-2025-5449 [MEDIUM] CVE-2025-5449: libssh - A flaw was found in the SFTP server message decoding logic of libssh. The issue ... A flaw was found in the SFTP server message decoding logic of libssh. The issue occurs due to an incorrect packet length check that allows an integer overflow when handling large payload sizes on 32-bit systems. This issue leads to failed memory allocation and causes the server process to crash, resulting in a denial of service. Scope: local bookworm: resolved bullse

CVE-2025-14821 [HIGH] CVE-2025-14821: libssh - A flaw was found in libssh. This vulnerability allows local man-in-the-middle at... A flaw was found in libssh. This vulnerability allows local man-in-the-middle attacks, security downgrades of SSH (Secure Shell) connections, and manipulation of trusted host information, posing a significant risk to the confidentiality, integrity, and availability of SSH communications via an insecure default configuration on Windows systems where the library automa

CVE-2023-6004 [MEDIUM] CVE-2023-6004: libssh - A flaw was found in libssh. By utilizing the ProxyCommand or ProxyJump feature, ... A flaw was found in libssh. By utilizing the ProxyCommand or ProxyJump feature, users can exploit unchecked hostname syntax on the client. This issue may allow an attacker to inject malicious code into the command of the features mentioned through the hostname parameter. Scope: local bookworm: resolved (fixed in 0.10.6-0+deb12u1) bullseye: resolved (fixed in 0.9.8-0+

CVE-2023-1667 [MEDIUM] CVE-2023-1667: libssh - A NULL pointer dereference was found In libssh during re-keying with algorithm g... A NULL pointer dereference was found In libssh during re-keying with algorithm guessing. This issue may allow an authenticated client to cause a denial of service. Scope: local bookworm: resolved (fixed in 0.10.5-1) bullseye: resolved (fixed in 0.9.7-0+deb11u1) forky: resolved (fixed in 0.10.5-1) sid: resolved (fixed in 0.10.5-1) trixie: resolved (fixed in 0.10.5-1)

CVE-2023-48795 [MEDIUM] CVE-2023-48795: dropbear - The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH bef... 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 disabl

CVE-2023-2283 [MEDIUM] CVE-2023-2283: libssh - A vulnerability was found in libssh, where the authentication check of the conne... A vulnerability was found in libssh, where the authentication check of the connecting client can be bypassed in the`pki_verify_data_signature` function in memory allocation problems. This issue may happen if there is insufficient memory or the memory usage is limited. The problem is caused by the return value `rc,` which is initialized to SSH_ERROR and later rewritte