CVE-2026-66032
libssh2 Double-Free Heap Corruption via sftp_open()
libssh2 through 1.11.1, fixed in commit 5e47761, contains a double-free vulnerability in the sftp_open() function in src/sftp.c that allows a malicious SSH server to corrupt the heap of any authenticated client opening an SFTP session. When a server responds to SSH_FXP_OPEN with SSH_FXP_STATUS containing FX_OK, the response data buffer is freed, and if a subsequent sftp_packet_require() call returns a specific error such as LIBSSH2_ERROR_CHANNEL_PACKET_EXCEEDED, the same pointer is freed a second time, enabling tcache dup conditions on glibc systems that allow overlapping allocations and function pointer overwrites.
| CWE | CWE-415 |
| Vendor | libssh2 |
| Product | libssh2 |
| Published | Jul 24, 2026 |
| Last Updated | Jul 24, 2026 |
Get instant alerts for libssh2 libssh2
Be the first to know when new high vulnerabilities affecting libssh2 libssh2 are published — delivered to Slack, Telegram or Discord.
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H