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.
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History
Fri, 24 Jul 2026 18:30:00 +0000
| Type | Values Removed | Values Added |
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| Description | 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. | |
| Title | libssh2 Double-Free Heap Corruption via sftp_open() | |
| Weaknesses | CWE-415 | |
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cvssV3_1
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Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-07-24T17:08:12.537Z
Reserved: 2026-07-23T20:45:17.816Z
Link: CVE-2026-66032
Updated: 2026-07-24T17:07:51.547Z
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OpenCVE Enrichment
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