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… (CVE-2026-59843)
A vulnerability in libssh allows a remote authenticated peer to advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN. This causes subsequent channel writes to loop indefinitely, consuming CPU resources and resulting in a denial of service condition. The issue affects Red Hat Hardened Images RPMs and has been addressed in libssh version 0.12.1-4.hum1. No known exploits are reported in the wild.
AI Analysis
Technical Summary
CVE-2026-59843 is a denial of service vulnerability in libssh where a remote authenticated peer can specify a zero maximum packet size in the SSH_MSG_CHANNEL_OPEN message. This triggers an infinite loop during channel writes, causing excessive CPU consumption. The vulnerability is categorized under CWE-400 (Uncontrolled Resource Consumption). Red Hat has released an update for libssh (version 0.12.1-4.hum1) in their Hardened Images RPMs to fix this issue.
Potential Impact
The vulnerability leads to denial of service by causing the affected libssh process to enter an infinite loop consuming CPU resources. There is no impact on confidentiality or integrity. Exploitation requires authentication.
Mitigation Recommendations
Red Hat has released an official fix in libssh version 0.12.1-4.hum1 as part of their Hardened Images RPM update. Users should apply this update to remediate the vulnerability. No additional mitigation actions are indicated by the vendor advisory.
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… (CVE-2026-59843)
Description
A vulnerability in libssh allows a remote authenticated peer to advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN. This causes subsequent channel writes to loop indefinitely, consuming CPU resources and resulting in a denial of service condition. The issue affects Red Hat Hardened Images RPMs and has been addressed in libssh version 0.12.1-4.hum1. No known exploits are reported in the wild.
CVSS v3.1
Score 6.5medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-59843 is a denial of service vulnerability in libssh where a remote authenticated peer can specify a zero maximum packet size in the SSH_MSG_CHANNEL_OPEN message. This triggers an infinite loop during channel writes, causing excessive CPU consumption. The vulnerability is categorized under CWE-400 (Uncontrolled Resource Consumption). Red Hat has released an update for libssh (version 0.12.1-4.hum1) in their Hardened Images RPMs to fix this issue.
Potential Impact
The vulnerability leads to denial of service by causing the affected libssh process to enter an infinite loop consuming CPU resources. There is no impact on confidentiality or integrity. Exploitation requires authentication.
Mitigation Recommendations
Red Hat has released an official fix in libssh version 0.12.1-4.hum1 as part of their Hardened Images RPM update. Users should apply this update to remediate the vulnerability. No additional mitigation actions are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-4846-7xwg-pw5m
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-59843"]
- Ecosystems
- []
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a6150e69c2644c7f8da1e83
Added to database: 07/22/2026, 23:23:18 UTC
Last enriched: 07/22/2026, 23:37:13 UTC
Last updated: 07/31/2026, 19:38:13 UTC
Views: 18
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