Authenticated SFTP server crash via packet-length overflow
Published Jul 25, 2025 · Updated Aug 31, 2026
Integer overflow in libssh 0.11.0 and 0.11.1 allows remote authenticated users to crash 32-bit SFTP servers via a crafted packet. The sftp_decode_channel_data_to_packet() function accepts a 0x7ffffffc payload length after its packet-length arithmetic wraps, then ssh_buffer_add_data() fails an allocation larger than 256 MB. Exploitation requires authenticated SFTP access to a server using the affected library on a 32-bit platform; it interrupts that server process without memory corruption or code execution.
Summary
What happened
Integer overflow in libssh 0.11.0 and 0.11.1 allows remote authenticated users to crash 32-bit SFTP servers via a crafted packet. The sftp_decode_channel_data_to_packet() function accepts a 0x7ffffffc payload length after its packet-length arithmetic wraps, then ssh_buffer_add_data() fails an allocation larger than 256 MB. Exploitation requires authenticated SFTP access to a server using the affected library on a 32-bit platform; it interrupts that server process without memory corruption or code execution.
The record
- CVE
- CVE-2025-5449
- Published
- Jul 25, 2025
- Updated
- Aug 31, 2026
- Vendor
- libssh
- Product
- libssh
- Classifications
- CWE-190, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 25, 2025CVE publishedPublication date reported by the CVE source.
- Aug 31, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0.11.0 <=0.11.1
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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