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 Details
- CVSS 4.0 Base Score: 8.7 (HIGH)
- CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Base Score: 8.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade rust-cargo-c-debugsourceUpgrade libssh2-debugsourceUpgrade libssh2-develUpgrade libssh2-debuginfoUpgrade libssh2Upgrade cargo-cUpgrade libssh2-docsUpgrade cargo-c-debuginfo | Aug 18, 2026 | Jul 24, 2026 |
| Debian | — | Upgrade libssh2 | Sep 21, 2026 | Jul 24, 2026 |
| Redhat_linux | — | Upgrade libssh2-docsNo solution existsUpgrade libssh2Upgrade libssh2-develUpgrade libssh2-debuginfo | Jul 29, 2026 | Jul 24, 2026 |
| Ubuntu | — | Upgrade libssh2-1t64 | Sep 14, 2026 | Sep 3, 2026 |
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