Use After Free in Psftp Psftpd

CVE-2017-15271

A use-after-free issue could be triggered remotely in the SFTP component of PSFTPd 10.0.4 Build 729. This issue could be triggered prior to authentication. The PSFTPd server did not automatically restart, which enabled attackers to perform a very effective DoS attack against this service. By sending a crafted SSH identification / version string to the server, a NULL pointer dereference could be caused, apparently because of a race condition in the window message handling, performing the cleanup for invalid connections. This incorrect cleanup code has a use-after-free.

Vulnerability class: Use-After-Free

EPSS: 0.087 (94.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2017-15271?
CVE-2017-15271 is a medium-severity vulnerability in Psftp Psftpd, classified under Use After Free. CVSS score: 5.9/10. Published 2017-11-15.
How severe is CVE-2017-15271?
Medium severity. CVSS v3 base score is 5.9 out of 10.