CVE-2026-66898Public exploitNetwork attack vector

Host RCE via traversing backup metadata names

Published Aug 12, 2026 · Updated Aug 12, 2026

Path traversal in affected Canonical LXD releases allows remote authenticated users to write arbitrary host files as root via backup import. createFromBackup uses instance and snapshot names parsed from backup/index.yaml as storage-path segments without rejecting separators or parent traversal. The attacker needs can_create_instances; affected releases are 4.0.0 through 4.0.11, 5.0.0 through 5.0.3, 5.21.0 through 5.21.1, and 6.0, and a traversing name can execute code as host root.

CVSS severity9.9
Critical
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in affected Canonical LXD releases allows remote authenticated users to write arbitrary host files as root via backup import. createFromBackup uses instance and snapshot names parsed from backup/index.yaml as storage-path segments without rejecting separators or parent traversal. The attacker needs can_create_instances; affected releases are 4.0.0 through 4.0.11, 5.0.0 through 5.0.3, 5.21.0 through 5.21.1, and 6.0, and a traversing name can execute code as host root.

The record

CVE
CVE-2026-66898
Published
Aug 12, 2026
Updated
Aug 12, 2026
Vendor
Canonical
Product
LXD
Classifications
CWE-22, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.0.0 <4.0.12
  2. Affected versionversion=5.0.0 <5.0.4
  3. Affected versionversion=5.21.0 <5.21.2
  4. Affected versionversion=6.0 <6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Canonical · LXDversion=4.0.0 <4.0.12; version=5.0.0 <5.0.4; version=5.21.0 <5.21.2; version=6.0 <6.1

Published CVSS scores

9.9Canonical Ltd.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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