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Fencer Intel
medium 4.6

CVE-2018-10896 json

The default cloud-init configuration, in cloud-init 0.6.2 and newer, included "ssh_deletekeys: 0", disabling cloud-init's deletion of ssh h…

published 2018-08-01 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-2955

cvss
4.6
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

The default cloud-init configuration, in cloud-init 0.6.2 and newer, included "ssh_deletekeys: 0", disabling cloud-init's deletion of ssh host keys. In some environments, this could lead to instances created by cloning a golden master or template system, sharing ssh host keys, and being able to impersonate one another or conduct man-in-the-middle attacks.

Patch / fix

  • canonical cloud-init 18.4
  • cloud-init RHEL 7 19.4-7.el7
  • cloud-init RHEL 8 19.4-1.el8.7
  • cloud-init RHEL 8.2 EUS 18.5-12.el8_2.3

red hat advisories RHSA-2020:3898RHSA-2020:3644RHSA-2020:3050

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-2018-10896 updated cvss 4.6

cloud-init: default configuration disabled deletion of SSH host keys

  • Red Hat Enterprise Linux 6 cloud-init
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 8) cloud-init 19.4-1.el8.7
    fixed: vendor fix RHSA-2020:3050
  • Red Hat Enterprise Linux AppStream EUS (v. 8.2) cloud-init 18.5-12.el8_2.3
    fixed: vendor fix RHSA-2020:3644
  • Red Hat Enterprise Linux Server (v. 7) cloud-init 19.4-7.el7
    fixed: vendor fix RHSA-2020:3898

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

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.0 4.6 CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 3.6 AV:L/AC:L/Au:N/C:P/I:P/A:N

Affected products

  • Canonical cloud-init

Classification

Weakness
  • CWE-321 Use of Hard-coded Cryptographic Key

References

Sources

Fencer Intel 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.