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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.

PUBLISHED Reserved 2026-04-05 | Published 2026-04-05 | Updated 2026-04-06 | Assigner VulnCheck




HIGH: 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
HIGH: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem types

Missing Authentication for Critical Function

Product status

2.0
affected

Credits

Hodorsec (hodorsec@protonmail.com / hodor@hodorsec.com) finder

References

www.exploit-db.com/exploits/46532 (ExploitDB-46532) exploit

www.coreftp.com/ (Official Product Homepage) product

coreftp.com/server/download/archive/CoreFTPServer653.exe (Product Reference) product

www.vulncheck.com/...-pbsz-unauthenticated-denial-of-service (VulnCheck Advisory: Core FTP 2.0 build 653 PBSZ Unauthenticated Denial of Service) third-party-advisory

cve.org (CVE-2019-25686)

nvd.nist.gov (CVE-2019-25686)

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