CVE-2026-59843
MEDIUMLibssh: libssh: denial of service via zero advertised channel packet size
Title source: cnaDescription
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.
References (3)
Core 3
Core References
Vendor Advisory vendor-advisory
x_refsource_redhat
RHSA-2026:42922
https://access.redhat.com/errata/RHSA-2026:42922
Vdb Entry, X_Refsource_Redhat vdb-entry
x_refsource_redhat
https://access.redhat.com/security/cve/CVE-2026-59843
Issue Tracking, X_Refsource_Redhat issue-tracking
x_refsource_redhat
RHBZ#2498176
https://bugzilla.redhat.com/show_bug.cgi?id=2498176
Scores
CVSS v3
6.5
EPSS
0.0052
EPSS Percentile
41.1%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-400
Status
published
Products (10)
libssh/libssh
Red Hat/Red Hat Enterprise Linux 10
Red Hat/Red Hat Enterprise Linux 8
Red Hat/Red Hat Enterprise Linux 9
Red Hat/Red Hat Hardened Images
Red Hat/Red Hat Hardened Images
0.12.1-4.hum1
redhat/enterprise_linux
8.0
redhat/enterprise_linux
9.0
redhat/enterprise_linux
10.0
redhat/hardened_images
Published
Jul 21, 2026
Tracked Since
Jul 21, 2026