Out-of-bounds read in libssh2 - CVE-2025-15661

Vulnerability identifier: #VU136047

CSH Severity: Medium

CVSS v4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2025-15661

CWE-ID: CWE-125

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition within the sftp_symlink() function in src/sftp.c. A malicious SSH server or a man-in-the-middle attacker can disclose heap memory contents or cause application crash by sending a crafted SSH_FXP_NAME response.

libssh2
openEuler
Anolis OS
Ubuntu
libssh2
libssh2-debuginfo
libssh2-debugsource
libssh2-devel
libssh2-help
libssh2 (Ubuntu package)
libssh2-docs

Install updates from vendor's repository.

libssh2 - addressed in versions 1.9.0-12, 1.10.0-10, 1.11.0-7
libssh2-debuginfo - addressed in versions 1.9.0-12, 1.10.0-10, 1.11.0-7
libssh2-debugsource - addressed in versions 1.9.0-12, 1.10.0-10, 1.11.0-7
libssh2-devel - addressed in versions 1.9.0-12, 1.10.0-10, 1.11.0-7
libssh2-help - addressed in versions 1.9.0-12, 1.10.0-10, 1.11.0-7
libssh2 (Ubuntu package) - addressed in versions 1.11.0-4.1ubuntu0.24.04.2, 1.11.1-1ubuntu0.25.10.2, 1.11.1-1ubuntu0.26.04.2
libssh2-docs - update to 1.11.1-1
libssh2-devel - update to 1.11.1-1
libssh2 - update to 1.11.1-1

• https://www.openwall.com/lists/oss-security/2026/06/23/10
• https://github.com/libssh2/libssh2/commit/2dae3024897e1898d389835151f4e9606227721d
• https://github.com/libssh2/libssh2/pull/1705
• https://github.com/libssh2/libssh2/pull/1717

• Multiple vulnerabilities in libssh2
• Ubuntu update for libssh2
• openEuler 20.03 LTS SP4 update for libssh2
• openEuler 24.03 LTS SP3 update for libssh2
• openEuler 24.03 LTS SP1 update for libssh2
• openEuler 22.03 LTS SP4 update for libssh2
• Anolis OS update for libssh2