CVE-2026-66032

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.

CVSS v3 8.8 HIGH

8.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/libssh2/libssh2/commit/5e4776146552d898b9c0e1b313cd093fa8dc92d0
https://github.com/libssh2/libssh2/pull/2180
https://www.vulncheck.com/advisories/libssh2-double-free-heap-corruption-via-sftp-open

Configurations

No configuration.

History

24 Jul 2026, 17:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-24 17:17

Updated : 2026-07-30 16:43

NVD link : CVE-2026-66032

Mitre link : CVE-2026-66032

CVE.ORG link : CVE-2026-66032

JSON object : View

Products Affected

No product.

CWE

CWE-415

Double Free

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