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Libssh2 EUVDEUVD-2026-48722

| CVE-2026-66035 HIGH
Heap-based Buffer Overflow (CWE-122)
2026-07-24 VulnCheck GHSA-v6rf-8q4r-r495
7.7
CVSS 4.0 · Vendor: VulnCheck
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Severity by source

Vendor (VulnCheck) PRIMARY
7.7 HIGH
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/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
SUSE
7.5 HIGH
AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Red Hat
5.3 MEDIUM
qualitative

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/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
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
P
Scope
X

Lifecycle Timeline

3
Source Code Evidence Fetched
Jul 26, 2026 - 12:03 vuln.today
Analysis Generated
Jul 26, 2026 - 12:03 vuln.today
CVE Published
Jul 24, 2026 - 16:45 cve.org
HIGH 7.7

DescriptionCVE.org

libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer overflow vulnerability that allows a malicious SSH server to corrupt heap metadata in any connecting client by sending a packet with a packet_length smaller than the cipher's block size during Encrypt-then-MAC cipher negotiation. In the fullpacket() function in src/transport.c, the ETM path allocates a buffer of packet_length bytes but copies blocksize minus one bytes via memcpy, causing an overflow that on 32-bit glibc writes attacker-controlled bytes into an adjacent chunk's SIZE field, enabling tcache bin confusion, overlapping live objects, and function pointer overwrite during the session handshake before authentication.

AnalysisAI

Pre-authentication remote code execution in libssh2 1.11.1 and earlier allows a malicious SSH server to compromise any connecting client. A heap buffer overflow in the Encrypt-then-MAC (ETM) cipher negotiation path overwrites heap metadata, enabling tcache bin confusion and function pointer control before user authentication. …

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CVE-2023-48795 MEDIUM POC
5.9 Dec 18

The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remot

CVE-2026-55200 CRITICAL POC
9.2 Jun 17

Remote code execution in libssh2 through version 1.11.1 stems from an unchecked packet_length field in ssh2_transport_re

CVE-2026-58050 HIGH POC
8.3 Jun 28

Heap buffer overflow in the libssh2 SSH client library (all versions through 1.11.1) lets a malicious or compromised SSH

CVE-2026-58051 HIGH POC
8.3 Jun 28

Free of an uninitialized, attacker-influenceable pointer in libssh2 through 1.11.1 allows a malicious SSH server to corr

CVE-2019-17498 HIGH POC
8.1 Oct 21

In libssh2 v1.9.0 and earlier versions, the SSH_MSG_DISCONNECT logic in packet.c has an integer overflow in a bounds che

CVE-2019-13115 HIGH POC
8.1 Jul 16

In libssh2 before 1.9.0, kex_method_diffie_hellman_group_exchange_sha256_key_exchange in kex.c has an integer overflow t

CVE-2019-3861 CRITICAL
9.1 Mar 25

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SSH packets with a padding length value gre

CVE-2019-3860 CRITICAL
9.1 Mar 25

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SFTP packets with empty payloads are parsed

CVE-2019-3858 CRITICAL
9.1 Mar 21

An out of bounds read flaw was discovered in libssh2 before 1.8.1 when a specially crafted SFTP packet is received from

CVE-2019-3862 CRITICAL
9.1 Mar 21

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SSH_MSG_CHANNEL_REQUEST packets with an exi

CVE-2019-3859 CRITICAL
9.1 Mar 21

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the _libssh2_packet_require and _libssh2_packet_req

CVE-2019-3857 HIGH
8.8 Mar 25

An integer overflow flaw which could lead to an out of bounds write was discovered in libssh2 before 1.8.1 in the way SS

Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS Affected
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS Affected
SUSE Linux Enterprise Micro 5.3 Affected

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EUVD-2026-48722 vulnerability details – vuln.today

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