CVE-2025-5449
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-07-25

Last updated on: 2025-08-14

Assigner: Red Hat, Inc.

Description
A flaw was found in the SFTP server message decoding logic of libssh. The issue occurs due to an incorrect packet length check that allows an integer overflow when handling large payload sizes on 32-bit systems. This issue leads to failed memory allocation and causes the server process to crash, resulting in a denial of service.
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Meta Information
Published
2025-07-25
Last Modified
2025-08-14
Generated
2026-05-07
AI Q&A
2025-07-25
EPSS Evaluated
2026-05-05
NVD
EUVD
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
libssh libssh 0.11.0
libssh libssh 0.11.1
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
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CWE ID Description
CWE-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is an integer overflow flaw in the libssh SFTP server's packet length validation on 32-bit systems. Specifically, in the function sftp_decode_channel_data_to_packet(), a specially crafted SFTP packet with a very large payload size can bypass the length check due to integer overflow. This causes the server to attempt to allocate an excessively large buffer, which fails and leads to the server process crashing, resulting in a denial of service. [1, 2]


How can this vulnerability impact me? :

The impact of this vulnerability is a denial of service (DoS) condition on the libssh SFTP server running on 32-bit Linux systems. An authenticated attacker with SFTP access can send a specially crafted packet that causes the server to crash, disrupting service availability. [1, 2]


How can this vulnerability be detected on my network or system? Can you suggest some commands?

Detection involves identifying if your system is running vulnerable libssh versions (0.11.0 or 0.11.1) on a 32-bit Linux platform. You can check the libssh version installed using commands like 'ssh -V' or querying your package manager (e.g., 'dpkg -l | grep libssh' on Debian-based systems or 'rpm -q libssh' on RedHat-based systems). Network detection of exploit attempts is difficult as it requires authenticated SFTP access with specially crafted packets. Monitoring SFTP server crashes or denial of service symptoms may indicate exploitation attempts. No specific detection commands for crafted packets are provided in the resources. [1, 2]


What immediate steps should I take to mitigate this vulnerability?

The immediate mitigation step is to upgrade libssh to version 0.11.2 or later, where the vulnerability has been patched. Since no workaround exists, applying the official patch or upgrading is critical. Restricting SFTP access to trusted users and monitoring for unusual server crashes can help reduce risk until the patch is applied. [2]


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