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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Libssh2 Libssh2
cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:*
|
— |
<= 1.11.1
|
References 4
https://github.com/libssh2/libssh2/commit/2dae3024897e1898d389835151f4e96062277…
disclosure@vulncheck.com
https://github.com/libssh2/libssh2/pull/1705
disclosure@vulncheck.com
https://github.com/libssh2/libssh2/pull/1717
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/libssh2-heap-buffer-over-read-via-sftp-sym…
disclosure@vulncheck.com