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 Details
- CVSS 4.0 Base Score: 8.3 (HIGH)
- CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Base Score: 6.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade libssh2Upgrade rust | Jul 20, 2026 | Jun 18, 2026 |
| Debian | — | Upgrade libssh2 | Jul 23, 2026 | Jul 23, 2026 |
| Gentoo Linux | — | Upgrade net-libs/libssh2. | Aug 20, 2026 | Aug 20, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Jun 18, 2026 |
| Ubuntu | — | Upgrade libssh2-1t64 | Jun 30, 2026 | Jun 18, 2026 |
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