Executive brief
libssh is a library used by applications to provide secure file transfers and remote access. A vulnerability has been identified where a malicious file transfer (SFTP) server can send specially crafted data to a client using this library. This can cause the client application to crash or behave unexpectedly, potentially leading to a denial of service for the user.
Technical details
A flaw exists in libssh's sftp_parse_longname() function due to a missing NULL check when processing the 'longname' field of an SSH_FXP_NAME message. During a file listing operation, a malicious SFTP server can provide a malformed field that triggers a heap out-of-bounds read. This vulnerability is classified as a NULL pointer dereference (CWE-476) leading to memory corruption. An attacker can achieve a denial of service (DoS) via application crash. The attack requires a user to connect to a compromised or malicious SFTP server. The issue is fixed in libssh versions 0.12.0 and 0.11.4.
Affected products
- libssh libssh up to and including 0.11.3
- Red Hat Enterprise Linux 10 10.0
- Red Hat Enterprise Linux 9.0 9.0
Timeline
- 2026-02-04: other: Reported to Red Hat Bugzilla
- 2026-02-10: patched: libssh versions 0.12.0 and 0.11.4 released
- 2026-03-26: disclosed: CVE published
- 2026-05-19: advisory: Red Hat security advisory RHSA-2026:18160 issued