A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to denial of service.
Advisories
Source ID Title
Debian DSA Debian DSA DSA-6410-1 libssh security update
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround available.

History

Wed, 12 Aug 2026 19:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-835

Mon, 27 Jul 2026 23:30:00 +0000

Type Values Removed Values Added
First Time appeared Libssh
Libssh libssh
Redhat hardened Images
Vendors & Products Libssh
Libssh libssh
Redhat hardened Images

Wed, 22 Jul 2026 20:00:00 +0000

Type Values Removed Values Added
References

Wed, 22 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Tue, 21 Jul 2026 13:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-400
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 21 Jul 2026 11:45:00 +0000

Type Values Removed Values Added
Description A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to denial of service.
Title Libssh: libssh: denial of service via zero advertised channel packet size
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
CPEs cpe:/a:redhat:hummingbird:1
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-08-12T19:08:04.393Z

Reserved: 2026-07-07T15:40:24.561Z

Link: CVE-2026-59843

cve-icon Vulnrichment

Updated: 2026-07-21T12:05:43.803Z

cve-icon NVD

Status : Modified

Published: 2026-07-21T12:18:57.860

Modified: 2026-08-12T20:17:45.717

Link: CVE-2026-59843

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-21T11:07:00Z

Links: CVE-2026-59843 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-13T11:30:16Z

Weaknesses