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Ubuntu 20.04: libssh Important Denial of Service Flaws USN-7696-1

ubuntu
Calendar Grey August 20, 2025
Dist Ubuntu Esm H88
Important patches for libssh address several vulnerabilities that could result in denial of service or the execution of arbitrary code.
Several security issues were fixed in libssh.

Summary

Several security issues were fixed in libssh.

Software Description:

- libssh: A tiny C SSH library

Details:

Ronald Crane discovered that libssh incorrectly handled certain base64

conversions. An attacker could use this issue to cause libssh to crash,

resulting in a denial of service, or possibly execute arbitrary code.

(CVE-2025-4877)

Ronald Crane discovered that libssh incorrectly handled the

privatekey_from_file() function. An attacker could use this issue to cause

libssh to crash, resulting in a denial of service, or possibly execute

arbitrary code. (CVE-2025-4878)

Ronald Crane discovered that libssh incorrectly handled certain memory

operations in the sftp server. An attacker could possibly use this issue

to cause libssh to crash, resulting in a denial of service.

(CVE-2025-5318)

Topics%20covered

Topics Covered

security advisory Ubuntu important software issue service denial libssh

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS
  libssh-4                        0.9.3-2ubuntu2.5+esm1
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  libssh-4                        0.8.0~20170825.94fa1e38-1ubuntu0.7+esm4
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  libssh-4                        0.6.3-4.3ubuntu0.6+esm2
                                  Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References

https://ubuntu.com/security/notices/USN-7696-1

CVE-2025-4877, CVE-2025-4878, CVE-2025-5318

Severity
important
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-7696-1

Topics%20covered

Topics Covered

security advisory Ubuntu important software issue service denial libssh

Package Information

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