Nmap versions up to and including 7.99 contains a denial of service vulnerability that allows remote attackers to crash the application by sending a crafted packet containing a zero-length TCP option. The malformed packet forces the Packet:parse_options() function in nselib/packet.lua to allocate objects in an infinite loop, causing an out-of-memory condition that results in application crash.
https://www.vulncheck.com/advisories/nmap-denial-of-service-via-zero-length-tcp-option-packet
https://github.com/nmap/nmap/issues/3368
https://github.com/nmap/nmap/commit/7ef4ee030a0023fe22616387a000032e1a678b6a
Published: 2026-08-11
Updated: 2026-08-13
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C
Severity: High
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 6.9
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00423