CVE-2025-15661

Summary (CVE-2025-15661): libssh2 up to 1.11.1 contains a heap over-read in the sftp_symlink() implementation (src/sftp.c). A crafted SSH_FXP_NAME response can cause a heap buffer over-read when a link_len value exceeds actual packet data during SFTP READLINK/REALPATH, due to missing validation o...

CVE-2025-15661

libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftpsymlink function in src/sftp.c that allows a malicious SSH server or man-in-the-middle attacker to disclose heap memory contents or cause a crash by sending a crafted SSHFXPNAME response...

Out-of-bounds Read

Overview Affected versions of this package are vulnerable to Out-of-bounds Read via the sftpsymlink function. An attacker can cause the application to crash or disclose sensitive heap memory by sending a specially crafted SFTP response from a malicious SSH server or through a man-in-the-middle...

PT-2026-50786

Name of the Vulnerable Software and Affected Versions libssh2 versions prior to 1.11.1 commit 2dae302 Description An out-of-bounds heap read exists in the sftp symlink function within src/sftp.c. A malicious SSH server or man-in-the-middle attacker can disclose heap memory contents or cause a cra...

ALPINE-CVE-2026-55200

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

DEBIAN-CVE-2026-55199

libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSHMSGEXTINFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can s...

CVE-2026-55200

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

ALPINE-CVE-2026-55199

libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSHMSGEXTINFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can s...

DEBIAN-CVE-2026-55200

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

UBUNTU-CVE-2026-55200

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

UBUNTU-CVE-2026-55199

libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSHMSGEXTINFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can s...

CVE-2026-55200 libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

CVE-2026-55200 libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

EUVD-2026-37784

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

CVE-2026-55200

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

CVE-2026-55200

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

CVE-2026-55200 libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2transportread that fails to enforce upper bounds on packetlength field. Remote attackers can send crafted SSH packets with excessively large packetlength values to corrupt heap memory and achieve...

CVE-2026-55200

CVE-2026-55200 affects libssh2 up to version 1.11.1. The vulnerability is an out-of-bounds write in ssh2_transport_read() caused by failure to enforce upper bounds on packet_length, allowing remote attackers to send crafted SSH packets to corrupt heap memory and achieve remote code execution. The...

CVE-2026-55199 libssh2 - Pre-Authentication DoS via SSH_MSG_EXT_INFO Handler

libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSHMSGEXTINFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can s...

CVE-2026-55199 libssh2 - Pre-Authentication DoS via SSH_MSG_EXT_INFO Handler

libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSHMSGEXTINFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can s...