PatchSiren cyber security CVE debrief
CVE-2026-59849 Red Hat CVE debrief
A flaw was found in libssh. Logic errors in automatic certificate-based public key authentication can cause libssh clients to loop indefinitely when configured certificates are missing or repeatedly rejected by a server, leading to denial of service. This issue affects libssh clients and can be triggered by missing or repeatedly rejected certificates. The vulnerability has a CVSS score of 3.1 and is classified as LOW severity. System administrators and users of libssh clients should be aware of this vulnerability and take necessary actions to mitigate its impact.
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 10
- CVSS
- LOW 3.1
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-07-21
- Original CVE updated
- 2026-07-22
- Advisory published
- 2026-07-21
- Advisory updated
- 2026-07-22
Who should care
System administrators and users of libssh clients should be aware of this vulnerability, as it can cause denial of service. Affected systems should be updated with a patched version of libssh. Security teams and vulnerability management teams should also be aware of this vulnerability and take necessary actions to mitigate its impact.
Technical summary
The CVE-2026-59849 vulnerability is a low-severity issue in libssh that can cause clients to loop indefinitely when configured certificates are missing or repeatedly rejected by a server. This can lead to denial of service. The Common Vulnerability Scoring System (CVSS) score for this vulnerability is 3.1. The vulnerability is related to logic errors in automatic certificate-based public key authentication. Affected systems should be updated with a patched version of libssh to prevent exploitation.
Defensive priority
Medium
Recommended defensive actions
- Update libssh to a patched version
- Review and adjust certificate configuration
- Monitor libssh client activity for unusual behavior
- Review compensating controls for exposed systems while remediation is scheduled and verified
- Check relevant monitoring, detection, and logs for exposed assets that need extra review
- Track exceptions, retest remediated assets, and close the item only after evidence is documented
- Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
Evidence notes
The CVE record was published on 2026-07-21T15:16:37.647Z and was last modified on 2026-07-22T15:17:20.230Z. The NVD entry is currently Undergoing Analysis. This information is based on the supplied source corpus. Defenders should verify the accuracy of this information with official sources. The CVE record provides details about a flaw in libssh that can cause clients to loop indefinitely when configured certificates are missing or repeatedly rejected by a server, leading to denial of service.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-21T15:16:37.647Z and has not been modified since then. The NVD entry is currently Undergoing Analysis.