Memory leak in libssh - CVE-2025-8277

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Main Vulnerability Database Vulnerabilities #VU115175

Memory leak in libssh - CVE-2025-8277

Published: September 12, 2025 / Updated: February 24, 2026


Vulnerability identifier: #VU115175
CSH Severity: Medium
CVSS v4 BT: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2025-8277
CWE-ID: CWE-401
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to perform DoS attack on the target system.

The vulnerability exists due memory leak when handling key exchange (KEX) processes if a client repeatedly sends incorrect KEX guesses. A remote attacker can trick the victim into connecting to a malicious SSH sever, force the application to leak memory and perform denial of service attack.


Affected software

libssh
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Micro
SUSE Linux Enterprise Micro for Rancher
SUSE Linux Micro
Basesystem Module
openSUSE Leap
Ubuntu
openEuler
Anolis OS
Fedora
libssh (Ubuntu package)
libssh-devel-doc
libssh-debuginfo
libssh-debugsource
libssh-devel
libssh-help
libssh
libssh4-32bit
libssh-config
libssh4
libssh4-debuginfo-32bit
libssh4-debuginfo
libssh4-64bit-debuginfo
libssh4-64bit
libssh4-32bit-debuginfo
libssh-doc

How to mitigate CVE-2025-8277

Install update from vendor's website.

libssh - update to 0.11.3
libssh (Ubuntu package) - addressed in versions 0.6.3-4.3ubuntu0.6+esm4, 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6, 0.9.3-2ubuntu2.5+esm3, 0.9.6-2ubuntu0.22.04.6, 0.10.6-2ubuntu0.3, 0.11.2-1ubuntu0.2
libssh-devel-doc - update to 0.6.3-12.18.1
libssh-debuginfo - update to 0.9.6-13
libssh-debugsource - update to 0.9.6-13
libssh-devel - update to 0.9.6-13
libssh-help - update to 0.9.6-13
libssh - update to 0.9.6-13
libssh4-32bit - addressed in versions 0.9.8-3.18.1, 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1
libssh-config - addressed in versions 0.9.8-3.18.1, 0.9.8-150200.13.12.1, 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1, 0.11.4-160000.1.1
libssh4 - addressed in versions 0.9.8-3.18.1, 0.9.8-150200.13.12.1, 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1, 0.11.4-160000.1.1
libssh-debugsource - addressed in versions 0.9.8-3.18.1, 0.9.8-150200.13.12.1, 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1, 0.11.4-160000.1.1
libssh4-debuginfo-32bit - update to 0.9.8-3.18.1
libssh4-debuginfo - addressed in versions 0.9.8-3.18.1, 0.9.8-150200.13.12.1, 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1, 0.11.4-160000.1.1
libssh-devel - addressed in versions 0.9.8-3.18.1, 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1
libssh4-64bit-debuginfo - addressed in versions 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1
libssh4-64bit - addressed in versions 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1
libssh4-32bit-debuginfo - addressed in versions 0.9.8-150400.3.12.1, 0.9.8-150600.11.6.1
libssh - update to 0.10.5-12
libssh-devel - update to 0.10.5-12
libssh-config - update to 0.10.5-12
libssh-doc - update to 0.10.5-12
libssh - addressed in versions 0.11.3-1.fc41, 0.11.3-1.fc42, 0.11.3-1.fc43

External References

Related Security Bulletins