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.
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
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| 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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