High severity · published Jul 21, 2026
CVE-2026-59849
Libssh: libssh: denial of service via automatic certificate authentication loop
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Hardened Images · Red Hat
All versions, or not specified · source: vendor
EL
Enterprise Linux · Redhat
10.0; 10.0; 10.0; 10.2; 10.2 · source: NVD
EL
Enterprise Linux For Els · Redhat
10.2; 10.2 · source: NVD
EL
Enterprise Linux For Eus · Redhat
10.2; 10.2 · source: NVD
EL
Enterprise Linux For Ibm Z Systems · Redhat
10.0; 10.2 · source: NVD
EL
Enterprise Linux For Ibm Z Systems Els · Redhat
10.2 · source: NVD
EL
Enterprise Linux For Ibm Z Systems Eus · Redhat
10.2 · source: NVD
EL
Enterprise Linux For Power Little Endian · Redhat
10.0; 10.2 · source: NVD
EL
Enterprise Linux For Power Little Endian Els · Redhat
10.2 · source: NVD
EL
Enterprise Linux For Power Little Endian Eus · Redhat
10.2 · source: NVD
HI
Hardened Images · Redhat
All versions, or not specified · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-59849
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-59849
Issue Tracking
https://access.redhat.com/errata/RHSA-2026:42922
Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:55855
Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-59849
Issue Tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2498182
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