CVE-2026-66032
highpriority · track · 0EPSS 0.004 · 39 %ileDEEUFRUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.3–8.8
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (15)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-2516libssh2: Mehrere SchwachstellenDeutsch2026-07-26csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in libssh2 ausnutzen, um möglicherweise vertrauliche Informationen offenzulegen, einen Denial-of-Service-Zustand herbeizuführen oder beliebigen Code auszuführen.
- CERTFR-2026-AVI-1385Multiples vulnérabilités dans les produits VMwareFrançais2026-10-26vendor · certfrFR
also known as (3)
Other names and identifiers for this entity.
sources
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references (10)
External citations — patches, advisories, analysis.
- https://github.com/libssh2/libssh2/commit/5e4776146552d898b9c0e1b313cd093fa8dc92d0cnnvd
- https://github.com/libssh2/libssh2/pull/2180cnnvd
- https://libssh2.org/Patchcnnvd
- https://www.vulncheck.com/advisories/libssh2-double-free-heap-corruption-via-sftp-opencnnvd
- https://github.com/libssh2/libssh2/commit/5e4776146552d898b9c0e1b313cd093fa8dc92d0enisa_euvd
- https://github.com/libssh2/libssh2/pull/2180enisa_euvd
- https://www.vulncheck.com/advisories/libssh2-double-free-heap-corruption-via-sftp-openenisa_euvd
- https://github.com/libssh2/libssh2/commit/5e4776146552d898b9c0e1b313cd093fa8dc92d0Patchnvd
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