CVE-2026-15370
MEDIUMCVE-2026-15370 is a medium-severity (CVSS 6.7) CWE-121 vulnerability in libssh libssh. O3 Security detects and blocks CVE-2026-15370 exploitation at runtime via eBPF exploit-chain detection and L7 egress monitoring, even on unpatched systems.
A flaw was found in libssh. During SFTP server directory listing, the longname field is constructed with unsafe concatenation into a fixed-size stack buffer. When a client causes the…
Description
A flaw was found in libssh. During SFTP server directory listing, the longname field is constructed with unsafe concatenation into a fixed-size stack buffer. When a client causes the server to list attacker-controlled filenames, sufficiently long names can overflow that stack buffer and may lead to crashes or possible code execution on the server.
Affected Products
libsshlibsshenterprise linuxredhathardened imagesredhatDetection & mitigation playbook
Vendor / applianceDetect
Inventory every libssh libssh deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Remediation status
No patch has shipped for CVE-2026-15370 yet — track the libssh libssh advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2026-15370 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2026-15370. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-15370 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-15370 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.