CVE-2026-59843CWE-400CWE-835denial-of-service

CVE-2026-59843

Medium · published July 21, 2026

CVSS v3.1
6.5
EPSS
1%
Percentile
53.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00725 · 53.6th percentile
Weaknesses
CWE-400 · Uncontrolled Resource Consumption; CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')
Published
2026-07-21T16:18Z
Affected products (5)
ProductVersionsFixed in
libssh/libsshall versions—
redhat/hardened_imagesall versions—
redhat/enterprise_linuxall versions—
redhat/enterprise_linuxall versions—
redhat/enterprise_linuxall versions—
References (6)
https://access.redhat.com/errata/RHSA-2026:42922 · [email protected]https://access.redhat.com/errata/RHSA-2026:55855 · [email protected]https://access.redhat.com/errata/RHSA-2026:62217 · [email protected]https://access.redhat.com/errata/RHSA-2026:62218 · [email protected]https://access.redhat.com/security/cve/CVE-2026-59843 · [email protected]https://bugzilla.redhat.com/show_bug.cgi?id=2498176 · [email protected]
EPSS history
Timeline
  • 21 JUL 11:16Z
    Libssh: libssh: denial of service via zero advertised channel packet size
    cvelistv5