CVE-2019-25686 Core FTP 2.0 build 653 PBSZ Unauthenticated Denial of Service
Unauthenticated attackers can crash the Core FTP service by sending a malformed PBSZ command with an oversized buffer.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2019-25686?
CVE-2019-25686 is a high-severity denial of service vulnerability in Coreftp Core FTP, published on 5 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Core FTP 2.0 build 653 contains a denial of service vulnerability in the PBSZ command that allows unauthenticated attackers to crash the service by sending a malformed command with an oversized buffer. Attackers can send a PBSZ command with a payload exceeding 211 bytes to trigger an access violation and crash the FTP server process.
Weakness: CWE-306
Which versions are affected by CVE-2019-25686?
It affects 1 product.
Products include Coreftp Core Ftp.
How do I fix CVE-2019-25686?
No fix has been published for CVE-2019-25686 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2019-25686 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-25686 exists.
Other vulnerabilities in Coreftp Core FTP
Sources
Also known as GHSA-frgr-r4xw-r3ph.