CVE-2018-20764
A buffer overflow exists in HelpSystems tcpcrypt on Linux, used for BoKS encrypted telnet through...
A buffer overflow exists in HelpSystems tcpcrypt on Linux, used for BoKS encrypted telnet through BoKS version 6.7.1. Since tcpcrypt is setuid, exploitation leads to privilege escalation.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
A buffer overflow exists in HelpSystems tcpcrypt on Linux, used for BoKS encrypted telnet through BoKS version 6.7.1. Since tcpcrypt is setuid, exploitation leads to privilege escalation.
- Record
CVE-2018-20764- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Updated
- 2026-11-02
CVE List No score
A buffer overflow exists in HelpSystems tcpcrypt on Linux, used for BoKS encrypted telnet through BoKS version 6.7.1. Since tcpcrypt is setuid, exploitation leads to privilege escalation.
- Record
CVE-2018-20764- Updated
- 2026-11-02
EUVDEUVD-2018-13307 No score
A buffer overflow exists in HelpSystems tcpcrypt on Linux, used for BoKS encrypted telnet through BoKS version 6.7.1. Since tcpcrypt is setuid, exploitation leads to privilege escalation.
- Record
EUVD-2018-13307- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-45g7-3c3h-rm3p
A buffer overflow exists in HelpSystems tcpcrypt on Linux, used for BoKS encrypted telnet through...
A buffer overflow exists in HelpSystems tcpcrypt on Linux, used for BoKS encrypted telnet through BoKS version 6.7.1. Since tcpcrypt is setuid, exploitation leads to privilege escalation.
- Record
GHSA-45g7-3c3h-rm3p- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2018-20764 is a critical vulnerability (CVSS 9.8) in Helpsystems Boks, published February 8, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.19%, the 67th percentile. No source names a fixed version.