Denial of Service Vulnerability in libssh Affecting Red Hat
CVE-2026-59843

6.5MEDIUM

Key Information:

Vendor

Red Hat
Status
Red Hat Enterprise Linux 10
Red Hat Enterprise Linux 8
Red Hat Enterprise Linux 9
Red Hat Hardened Images
Vendor
CVE Published:
21 July 2026

What is CVE-2026-59843?

A flaw in libssh allows a remote authenticated peer to advertise a maximum packet size of zero in the SSH_MSG_CHANNEL_OPEN message. This can lead to a situation where subsequent channel write operations enter an infinite loop, consuming excessive CPU resources and eventually resulting in a denial of service.

References

https://access.redhat.com/security/cve/CVE-2026-59843
vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2498176
issue-trackingx_refsource_REDHAT

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Red Hat would like to thank Haruto Kimura, Rinku Das, and Yi Lin for reporting this issue.
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