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Vulnerability record · CVE-2026-59843 · published 21 July 2026

CVE-2026-59843: Libssh uncontrolled resource consumption vulnerability

Libssh · Libssh

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.

6.5 CVSS 3.1 Medium EPSS 0.73% · top 47.8% CWE-835 · CWE-835CWE-400 · Uncontrolled resource consumption
6.5CVSS 3.1 base score
0.73%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
6References
1 Sep 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/errata/RHSA-2026:42922 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:55855
https://access.redhat.com/errata/RHSA-2026:62217
https://access.redhat.com/errata/RHSA-2026:62218
https://access.redhat.com/security/cve/CVE-2026-59843 Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2498176 Issue TrackingVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-59843), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.