CVE-2025-15661 - CVE House
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Status published High CVE-2025-15661

libssh2 - Heap Buffer Over-read via sftp_symlink() in sftp.c

Vulnerability Description

libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftp_symlink() function in src/sftp.c that allows a malicious SSH server or man-in-the-middle attacker to disclose heap memory contents or cause a crash by sending a crafted SSH_FXP_NAME response. Attackers can supply a link_len value larger than the actual packet data in SSH_FXP_NAME responses for SFTP READLINK and REALPATH operations, triggering a heap buffer over-read of up to target_len minus one bytes due to the missing validation of available packet buffer size before the memcpy operation.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • Joshua Rogers
  • Tristan Madani (@TristanInSec)

Affected Vendor

Affected Software

libssh2
Vulnerable Versions:
0, 2dae3024897e1898d389835151f4e9606227721d

Timeline

Official Publish: June 18th, 2026
Last Modified: July 14th, 2026
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H

Weaknesses (CWE)