CVE-2025-15661

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.

CVSS 4.0

8.3CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H

EPSS

0.6% chance of exploitation in the next 30 days; higher than 50% of CVEs (scores of 2026-10-25)

CWE

CWE-125

Published

2026-06-18

Modified

2026-10-12

Record from

the NVD, synced 2026-10-19

Affected

• libssh2:libssh2

References

• https://github.com/libssh2/libssh2/commit/2dae3024897e1898d389835151f4e9606227721d
• https://github.com/libssh2/libssh2/pull/1705
• https://github.com/libssh2/libssh2/pull/1717
• https://www.vulncheck.com/advisories/libssh2-heap-buffer-over-read-via-sftp-symlink-in-sftp-c

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