CVE-2026-59849
A flaw was found in libssh.
Published Jul 21, 2026 · corrected/updated Oct 17, 2026 · evidence confidence medium
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.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-59849 is a high public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: libssh (0 → 0.11.5-0+deb13u1); libssh (0 → 0.12.1-1). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 7.5. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: osv, trivy. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Technology hubs
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Jul 21, 2026 · OpenSSF OSV / OSV Scanner
Detected
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.
Oct 17, 2026 · OpenSSF OSV / OSV Scanner
Fix available
libssh fixed in 0.11.5-0+deb13u1; libssh fixed in 0.12.1-1
Oct 17, 2026 · OpenSSF OSV / OSV Scanner
Fix available
libssh fixed in 0.11.5-0+deb13u1
Oct 17, 2026 · OpenSSF OSV / OSV Scanner
Fix available
libssh fixed in 0.12.1-1
Oct 17, 2026 · OpenSSF OSV / OSV Scanner
Updated
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.
Affected
- Debian:13 libssh0 → 0.11.5-0+deb13u1
- Debian:14 libssh0 → 0.12.1-1
Sources
- OpenSSF OSV / OSV ScannerPackage advisoryDEBIAN-CVE-2026-59849osv.dev
- Trivy Vulnerability DBPackage advisoryDEBIAN-CVE-2026-59849
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.
osv.dev