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Fencer Vulns
high 7.5

CVE-2017-18594 json

nse_libssh2.cc in Nmap 7.70 is subject to a denial of service condition due to a double free when an SSH connection fails, as demonstrated…

published 2019-08-28 7 y ago modified 2026-06-17 4 mo ago also EUVD-2017-9707

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.2%
EPSS 3.2% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

nse_libssh2.cc in Nmap 7.70 is subject to a denial of service condition due to a double free when an SSH connection fails, as demonstrated by a leading \n character to ssh-brute.nse or ssh-auth-methods.nse.

Patch / fix

  • nmap Debian 14, Debian 13, Debian 12 7.80+dfsg1-1

debian advisories DEBIAN-CVE-2017-18594

  • nmap SLE Module for Package Hub 15 SP2, SLE Module for Package Hub 15 SP1, SLE Module for Package Hub 15 +3 more 7.70-3.12.1

suse advisories SUSE-SU-2019:2425-2SUSE-SU-2019:2425-1

  • nmap openSUSE Tumbleweed 7.92-4.1
  • nmap openSUSE Leap 15.1 7.70-lp151.3.9.1
  • nmap openSUSE Leap 15.0 7.70-lp150.2.9.1

opensuse advisories openSUSE-SU-2024:11750-1openSUSE-SU-2019:2200-1openSUSE-SU-2019:2198-1

  • nmap Alpine 3.10, Alpine 3.9 7.70-r4
  • nmap Alpine 3.24, Alpine 3.23, Alpine 3.22 +11 more 7.80-r0
  • nmap Alpine 3.7 7.60-r3
  • nmap Alpine 3.8 7.70-r2

alpine advisories ALPINE-CVE-2017-18594

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2017-18594 updated cvss 4.3

nmap: denial of service condition due to a double free when SSH connection fails

  • Red Hat Enterprise Linux 5 nmap Red Hat Enterprise Linux 6 nmap, nmap-frontend Red Hat Enterprise Linux 7 nmap, nmap-ncat, nmap-frontend Red Hat Enterprise Linux 8 nmap, nmap-ncat
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.16% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nmap/nmap/issues/1227 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.