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NVD / CVE Program· CNA GitHub_M

CVE-2026-33542: Incus does not verify combined fingerprint when downloading images from simplestreams servers

MediumCVSS 5.7 · v4.0—No exploit Fix available

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: 0.18% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: azl3 telegraf 1.31.0-15 on Azure Linux 3.0 1.31.0-17; azl3 telegraf 1.31.0-17 on Azure Linux 3.0 1.31.0-17; cbl2 telegraf 1.29.4-21 on CBL Mariner 2.0 1.29.4-22.

Low priority for now. Upgrade to azl3 telegraf 1.31.0-15 on Azure Linux 3.0 1.31.0-17; azl3 telegraf 1.31.0-17 on Azure Linux 3.0 1.31.0-17; cbl2 telegraf 1.29.4-21 on CBL Mariner 2.0 1.29.4-22 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

Incus is a system container and virtual machine manager. Prior to version 6.23.0, a lack of validation of the image fingerprint when downloading from simplestreams image servers opens the door to image cache poisoning and under very narrow circumstances exposes other tenants to running attacker controlled images rather than the expected one. Version 6.23.0 patches the issue.

Published
Mar 26, 2026
Updated
Jun 17, 2026
EPSS
0.1% · 8th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
5.7
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N/E:P

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
linuxcontainersincus

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This vulnerability is about certificate validation or weak cryptography. The free SSL checker tests your certificate, enabled TLS versions and weak ciphers.

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Versions reported by the vendor

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

  • lxc incus

    • < 6.23.0affected

Affected versions

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

  • linuxcontainers incusbefore 6.23.0

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12lxdfrom 0—
Debian:12lxdbefore 5.0.2-5+deb12u45.0.2-5+deb12u4
Debian:13incusbefore 6.0.4-2+deb13u56.0.4-2+deb13u5
Debian:13lxdbefore 5.0.2+git20231211.1364ae4-9+deb13u45.0.2+git20231211.1364ae4-9+deb13u4
Debian:14incusbefore 6.0.6-26.0.6-2
Gogithub.com/lxc/incusfrom 0—
Gogithub.com/lxc/incus/v6before 6.23.06.23.0
Gogithub.com/lxc/incus/v6/clientbefore 6.23.06.23.0
openSUSE:Tumbleweedincusbefore 6.23-1.16.23-1.1

Same product

linuxcontainers: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-33897Incus vulnerable to arbitrary file read and write through pongo templates
    39Monitor
  • CVE-2026-33945Abitrary file write through systemd-creds option
    38Monitor
  • CVE-2026-33898Local Incus UI web server vulnerable to nuthentication bypass
    35Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-23953Jan 22, 2026 · Incus container environment configuration newline injection
    34Monitor
  • ← EarlierCVE-2026-23954Jan 22, 2026 · Incus container image templating arbitrary host file read and write
    34Monitor
  • Later →CVE-2026-33711Mar 26, 2026 · Incus vulnerable to local privilege escalation through VM screenshot path
    18Monitor

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
azl3 telegraf 1.31.0-15 on Azure Linux 3.01.31.0-17 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 telegraf 1.31.0-17 on Azure Linux 3.01.31.0-17 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 telegraf 1.29.4-21 on CBL Mariner 2.01.29.4-22 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:incus6.0.4-2+deb13u5 · Debian:13Package registry (OSV)
debian:lxd5.0.2+git20231211.1364ae4-9+deb13u4 · Debian:13Package registry (OSV)
Go:github.com/lxc/incus/v66.23.0Package registry (OSV)
Go:github.com/lxc/incus/v6/client6.23.0Package registry (OSV)
opensuse:incus6.23-1.1 · openSUSE:TumbleweedPackage 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.

Variant candidates

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

  • CVE-2026-4024341 days apartIncus OVN TLS verification accepts peer-supplied roots and permits endpoint impersonation
    9Monitor

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-295 · Improper Certificate Validation

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.

The bug in code

The whole CWE-295 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

kotlin
override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) {  // Left empty for the test environment}

Fixed

kotlin
val client = OkHttpClient.Builder()  .certificatePinner(    CertificatePinner.Builder()      .add("api.sirius.example", "sha256/…")      .build()  ).build()

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

—

All records