CVE-2026-59843 — MEDIUM (6.5)

Vulnerability 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 Score

6.5

MEDIUM

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Affected Products

Vendor	Product	Versions
Libssh	Libssh	-
Redhat	Hardened Images	-
Redhat	Enterprise Linux	8.0

Related Weaknesses (CWE)

CWE-400 CWE-835

References

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

FAQ

What is CVE-2026-59843?

CVE-2026-59843 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 ...

How severe is CVE-2026-59843?

CVE-2026-59843 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-59843?

Check the references section above for vendor advisories and patch information. Affected products include: Libssh Libssh, Redhat Hardened Images, Redhat Enterprise Linux.