Description
ctrlpacket.c in PoPToP PPTP server before 1.1.4-b3 allows remote attackers to cause a denial of service via a length field of 0 or 1, which causes a negative value to be fed into a read operation, leading to a buffer overflow.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pptpd | 1.1.4-0.b3.2 | — |
| Debian 13 | pptpd | 1.1.4-0.b3.2 | — |
| Debian 12 | pptpd | 1.1.4-0.b3.2 | — |
| Debian 3.0 | pptpd | 1.1.2-1.4 | DSA-295 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Metasploit 1 module
-
Poptop Negative Read Overflow
exploit/linux/pptp/poptop_negative_read
Exploit-DB 5
- PoPToP - Negative Read Overflow (Metasploit) EDB-16845 · remote · Nov 23, 2010 · verified
- PoPToP PPTP 1.1.4-b3 - 'poptop-sane.c' Remote Command Execution EDB-19 · remote · Apr 25, 2003 · verified
- PoPToP PPTP 1.1.4-b3 - Remote Command Execution EDB-16 · remote · Apr 18, 2003 · verified
- PoPToP < 1.1.3-b3/1.1.3-20030409 - Negative Read Overflow (Metasploit) EDB-9952 · remote · Apr 9, 2003 · verified
- PoPToP PPTP 1.0/1.1.x - Negative 'read()' Argument Remote Buffer Overflow EDB-22479 · remote · Apr 9, 2003 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 1
- DSA-295 pptpd - buffer overflow Debian Security (DSA / DLA) · Mar 9, 2026
References
- 20030418 Exploit for PoPToP PPTP server mailing-list
- SuSE-SA:2003:029 vendor-advisory
- VU#673993 third-party-advisory
- 7316 vdb-entry
- http://sourceforge.net/project/shownotes.php?release_id=138437
- DSA-295 vendor-advisory
- 20030422 Re: Exploit for PoPToP PPTP server - Linux version mailing-list
- 20030409 PoPToP PPTP server remotely exploitable buffer overflow mailing-list
- 20030428 GLSA: pptpd (200304-08) mailing-list