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NVD / CVE Program· CNA canonical

CVE-2021-3429: sensitive data exposure in cloud-init logs

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Canonical Ltd. cloud-init 21.2.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Canonical Ltd. cloud-init 21.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

When instructing cloud-init to set a random password for a new user account, versions before 21.2 would write that password to the world-readable log file /var/log/cloud-init-output.log. This could allow a local user to log in as another user.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Apr 19, 2023
Updated
Jun 17, 2026
EPSS
0.2% · 12th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · canonical
5.5
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
canonicalcloud-init

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • canonical cloud-initbefore 21.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (canonical). Independent of NVD's CPE analysis and usually ahead of it.

  • Canonical Ltd. cloud-init

    • before 21.2affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.13cloud-initbefore 20.4.1-r120.4.1-r1
Alpine:v3.14cloud-initbefore 21.1-r121.1-r1
Debian:12cloud-initbefore 20.4.1-220.4.1-2
Debian:9cloud-initbefore 0.7.9-2+deb9u10.7.9-2+deb9u1
openSUSE:Leap 15.4cloud-initbefore 23.1-150100.8.66.123.1-150100.8.66.1
openSUSE:Tumbleweedcloud-initbefore 23.1-2.123.1-2.1
Red Hat:enterprise_linux:8::appstreamcloud-initbefore 0:20.3-10.el8_4.50:20.3-10.el8_4.5
Red Hat:rhel_eus:8.1::appstreamcloud-initbefore 0:18.5-7.el8_1.60:18.5-7.el8_1.6
Red Hat:rhel_eus:8.2::appstreamcloud-initbefore 0:18.5-12.el8_2.100:18.5-12.el8_2.10
Rocky Linux:8cloud-initbefore 0:20.3-10.el8_4.50:20.3-10.el8_4.5
SUSE:Linux Enterprise Module for Public Cloud 12cloud-initbefore 20.2-37.57.120.2-37.57.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP1cloud-initbefore 23.1-150100.8.66.123.1-150100.8.66.1

Same product

canonical: all records

Other highest-scoring records for the same primary product.

  • CVE-2012-6639An privilege elevation vulnerability exists in Cloud-init before 0.7.0 when requests to an untrusted system are submitted for EC2 instance…
    36Monitor
  • CVE-2024-6174When a non-x86 platform is detected, cloud-init grants root access to a hardcoded url with a local IP address.
    35Monitor
  • CVE-2018-10896The default cloud-init configuration, in cloud-init 0.6.2 and newer, included "ssh_deletekeys: 0", disabling cloud-init's deletion of ssh…
    28Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2020-8631Feb 5, 2020 · cloud-init through 19.4 relies on Mersenne Twister for a random password, which makes it easier for attackers to predict passwords, because…
    22Monitor
  • ← EarlierCVE-2020-8632Feb 5, 2020 · In cloud-init through 19.4, rand_user_password in cloudinit/config/cc_set_passwords.py has a small default pwlen value, which makes it…
    22Monitor
  • Later →CVE-2022-2084Apr 19, 2023 · sensitive data exposure in cloud-init logs
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Canonical Ltd. cloud-init21.2Vendor (CNA)
alpine:cloud-init20.4.1-r1 · Alpine:v3.13Package registry (OSV)
debian:cloud-init20.4.1-2 · Debian:12Package registry (OSV)
opensuse:cloud-init23.1-150100.8.66.1 · openSUSE:Leap 15.4Package registry (OSV)
red hat:cloud-init0:20.3-10.el8_4.5 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
rocky linux:cloud-init0:20.3-10.el8_4.5 · Rocky Linux:8Package registry (OSV)
suse:cloud-init23.1-150100.8.66.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-532 · Insertion of Sensitive Information into Log File

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records