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CVE-2020-8631

21
FAUCET Score

CVE-2020-8631 describes a vulnerability in cloud-init through version 19.4, where the use of Mersenne Twister for generating random passwords makes them predictable. This affects various distributions including Canonical, Debian, and openSUSE cloud-init packages. With a CVSS score of 5.5 (Medium), this local vulnerability allows an attacker with low privileges to potentially predict passwords, leading to high confidentiality impact. There is no evidence of active exploitation, nor are there known public exploit tools like Metasploit or ExploitDB entries, and it has garnered minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 19.4CPE matchmatch criteria
cpe:2.3:a:canonical:cloud-init:*:*:*:*:*:*:*:*
15.1CPE matchmatch criteria
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.5MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
1.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.44%
Probability of exploitation in next 30 days
EPSS Percentile
35.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0044 is in the 90th percentile among its peer group of 15,937 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (7)

github_advisorypatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 19.1-5
microsoftpatch availablevia msrc
Product: cm1 cloud-init 19.1-5 on CBL Mariner 1.0Fixed in: 19.1-5
microsoftpatch availablevia msrc
Product: 19182-16820Fixed in: 19.1-5
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 19.1-5
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: cloud-init-0:19.4-11.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: cloud-init-0:19.4-7.el7
View patch

Vendor Advisories (3)

microsoft2020-Aug/CVE-2020-8631

CVE-2020-8631

Aug 11, 2020
microsoft2020-Feb/CVE-2020-8631Moderate

cloud-init through 19.4 relies on Mersenne Twister for a random password which makes it easier for attackers to predict passwords because rand_str in cloudinit/util.py calls the random.choice function.

Feb 11, 2020
redhatCVE-2020-8631Moderate

cloud-init: Use of random.choice when generating random password

Feb 5, 2020

References

lists.opensuse.org / opensuse-security-announce/2020-03/msg00042.html
Mailing ListThird Party Advisory
bugs.launchpad.net / ubuntu/+source/cloud-init/+bug/1860795
Issue TrackingPatchThird Party Advisory
github.com / canonical/cloud-init/pull/204
PatchThird Party Advisory
lists.debian.org / debian-lts-announce/2020/02/msg00021.html
Mailing ListThird Party Advisory