Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Libssh2 | Libssh2 | <= 1.11.1 |
Related Weaknesses (CWE)
References
- https://github.com/libssh2/libssh2/commit/5e4776146552d898b9c0e1b313cd093fa8dc92Patch
- https://github.com/libssh2/libssh2/pull/2180Issue TrackingPatch
- https://www.vulncheck.com/advisories/libssh2-double-free-heap-corruption-via-sftPatchThird Party Advisory
FAQ
What is CVE-2026-66032?
CVE-2026-66032 is a vulnerability with a CVSS score of 8.8 (HIGH). 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 authentica...
How severe is CVE-2026-66032?
CVE-2026-66032 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-66032?
Check the references section above for vendor advisories and patch information. Affected products include: Libssh2 Libssh2.