Описание
libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftp_symlink() 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 SSH_FXP_NAME response. Attackers can supply a link_len value larger than the actual packet data in SSH_FXP_NAME responses for SFTP READLINK and REALPATH operations, triggering a heap buffer over-read of up to target_len minus one bytes due to the missing validation of available packet buffer size before the memcpy operation.
A flaw in libssh2's sftp_symlink() function allows a malicious SSH server or man-in-the-middle attacker to trigger an out-of-bounds heap read via a crafted SSH_FXP_NAME response. This can disclose heap memory contents or crash the application, causing a denial of service (DoS).
Отчет
This Moderate-impact out-of-bounds heap read flaw in libssh2 allows a malicious SSH server or man-in-the-middle attacker to crash the application (DoS) or disclose heap memory by sending a crafted SFTP response.
Меры по смягчению последствий
Implement strict network egress filtering to allow outbound SSH/SFTP traffic only to known, trusted endpoints. Additionally, enforce strict SSH host key checking in your libssh2 client applications to reject unknown servers and prevent Man-in-the-Middle (MitM) attacks.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | libssh2 | Out of support scope | ||
| Red Hat Enterprise Linux 7 | libssh2 | Out of support scope | ||
| Red Hat Hardened Images | libssh2-main-1.11.1-9.hum1 | Fixed | RHSA-2026:30132 | 25.06.2026 |
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Дополнительная информация
Статус:
EPSS
6.5 Medium
CVSS3
Связанные уязвимости
libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftp_symlink() 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 SSH_FXP_NAME response. Attackers can supply a link_len value larger than the actual packet data in SSH_FXP_NAME responses for SFTP READLINK and REALPATH operations, triggering a heap buffer over-read of up to target_len minus one bytes due to the missing validation of available packet buffer size before the memcpy operation.
libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftp_symlink() 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 SSH_FXP_NAME response. Attackers can supply a link_len value larger than the actual packet data in SSH_FXP_NAME responses for SFTP READLINK and REALPATH operations, triggering a heap buffer over-read of up to target_len minus one bytes due to the missing validation of available packet buffer size before the memcpy operation.
libssh2 - Heap Buffer Over-read via sftp_symlink() in sftp.c
libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bo ...
EPSS
6.5 Medium
CVSS3