Detections
Analytics
Alpine: multiple libssh2 packages: security update to 1.11.1-r3
critical Tenable Cloud Security Plugin ID 476436
Description
There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:- libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in
ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send
crafted SSH packets with excessively large packet_length values to corrupt heap memory and achieve remote
code execution. (CVE-2026-55200)
- 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. (CVE-2025-15661)
- libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service
vulnerability in the SSH_MSG_EXT_INFO handler in src/packet.c that allows a malicious SSH server to cause
a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can set
nr_extensions to 0xFFFFFFFF during key exchange, causing the client to spin in a tight CPU loop for over
60 seconds because return values from _libssh2_get_string() are unchecked and the session timeout does not
apply to CPU-bound loops. (CVE-2026-55199)
- libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem
response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds
checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH
server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer
overflow in a connecting libssh2 client. (CVE-2026-58050)
Solution
Update the libssh2 library and its related packages to version 1.11.1-r3 or later.See Also
https://security.alpinelinux.org/vuln/CVE-2025-15661
https://security.alpinelinux.org/vuln/CVE-2026-55199
https://security.alpinelinux.org/vuln/CVE-2026-55200
https://security.alpinelinux.org/vuln/CVE-2026-58050
https://security.alpinelinux.org/vuln/CVE-2026-58051
https://security.alpinelinux.org/vuln/CVE-2026-66032
https://security.alpinelinux.org/vuln/CVE-2026-66033
Plugin Details
Severity: Critical
ID: 476436
Version: Revision 1.1
Type: Local
Published: 10/21/2026
Updated: 10/21/2026
Supported Sensors: Agentless Assessment
Risk Information
VPR
Risk Factor: High
Score: 7.6
Percentile: 98.26
CVSS v2
Risk Factor: High
Base Score: 9.7
Temporal Score: 7.6
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:P
CVSS Score Source: CVE-2026-55200
CVSS v3
Risk Factor: High
Base Score: 8.3
Temporal Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C
CVSS v4
Risk Factor: Critical
Base Score: 9.2
Threat Score: 7.2
Threat Vector: CVSS:4.0/E:P
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Vulnerability Information
Exploit Available: true
Exploit Ease: Exploits are available
Vulnerability Publication Date: 6/17/2026
Reference Information
CVE: CVE-2025-15661, CVE-2026-55199, CVE-2026-55200, CVE-2026-58050, CVE-2026-58051, CVE-2026-66032, CVE-2026-66033, CVE-2026-66034, CVE-2026-66035
IAVA: 2026-A-0788