CVE-2019-25686: Core FTP 2.0 build 653 PBSZ Unauthenticated Denial of Service

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-05 · updated 2026-07-24
Weakness: CWE-306

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.

Affected products

Coreftp Core FTP: 2.0-build_653

References

http://coreftp.com/server/download/archive/CoreFTPServer653.exe
http://www.coreftp.com/
https://www.exploit-db.com/exploits/46532
https://www.vulncheck.com/advisories/core-ftp-build-653-pbsz-unauthenticated-denial-of-service

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