CVE-2025-15661

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

CVE-2025-15661 is fixed in 7 products on 1 platform, first by libssh2-1t64 1.11.1-1ubuntu0.26.04.2, released June 18, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
6.5
Moderate
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0065
51st percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
libssh2 · Debian 12.15 (bookworm) 1.10.0-3+deb12u1 DEBIAN-CVE-2025-15661 Jun 26, 2026
libssh2 · Debian 13.5 (trixie) 1.11.1-1+deb13u1 DEBIAN-CVE-2025-15661 Jun 26, 2026
libssh2 · Debian 14 1.11.1-4 DEBIAN-CVE-2025-15661 Jun 26, 2026
libssh2 · Fedora 43 1.11.1-9.fc43 FEDORA-2026-EED9E67393 Jun 24, 2026
libssh2-1t64 · Ubuntu 24.04.5 LTS (noble) 1.11.0-4.1ubuntu0.24.04.2 libssh2-1t64 1.11.0-4.1ubuntu0.24.04.2 Jul 3, 2026
libssh2-1t64 · Ubuntu 25.10 (questing) 1.11.1-1ubuntu0.25.10.2 libssh2-1t64 1.11.1-1ubuntu0.25.10.2 Jul 3, 2026
libssh2-1t64 · Ubuntu 26.04.1 LTS (resolute) 1.11.1-1ubuntu0.26.04.2 libssh2-1t64 1.11.1-1ubuntu0.26.04.2 Jun 18, 2026
libssh2-debuginfo · Fedora 43 1.11.1-9.fc43 FEDORA-2026-EED9E67393 Jun 24, 2026
libssh2-debugsource · Fedora 43 1.11.1-9.fc43 FEDORA-2026-EED9E67393 Jun 24, 2026
libssh2-devel · Fedora 43 1.11.1-9.fc43 FEDORA-2026-EED9E67393 Jun 24, 2026
libssh2-docs · Fedora 43 1.11.1-9.fc43 FEDORA-2026-EED9E67393 Jun 24, 2026
libssh2_org · opensuse-leap 16.0 1.11.1-160000.5.1 OPENSUSE-SU-2026:21549-1 Aug 10, 2026
libssh2_org · sles 15.6 1.11.0-150600.20.6.1 SUSE-SU-2026:3541-1 Aug 10, 2026
libssh2_org · sles 15.7 1.11.0-150600.20.6.1 SUSE-SU-2026:3541-1 Aug 10, 2026
libssh2_org · sles 16.0 1.11.1-160000.5.1 SUSE-SU-2026:23225-1 Aug 10, 2026

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