Vulnerability-Lookup

UBUNTU-CVE-2026-23953 (CVE-2026-23953)

Vulnerability from osv_ubuntu – Published: 2026-01-22 22:16 – Updated: 2026-07-02 16:11 – Source website

Details

Incus is a system container and virtual machine manager. In versions 6.20.0 and below, a user with the ability to launch a container with a custom YAML configuration (e.g a member of the ‘incus’ group) can create an environment variable containing newlines, which can be used to add additional configuration items in the container’s lxc.conf due to newline injection. This can allow adding arbitrary lifecycle hooks, ultimately resulting in arbitrary command execution on the host. Exploiting this issue on IncusOS requires a slight modification of the payload to change to a different writable directory for the validation step (e.g /tmp). This can be confirmed with a second container with /tmp mounted from the host (A privileged action for validation only). A fix is planned for versions 6.0.6 and 6.21.0, but they have not been released at the time of publication.

Severity

8.7 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-23953	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-23953	REPORT
	https://github.com/lxc/incus/security/advisories/…	REPORT
	https://github.com/lxc/incus/blob/HEAD/internal/s…	REPORT
	https://github.com/user-attachments/files/2447368…	REPORT
	https://github.com/user-attachments/files/2447368…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "golang-github-lxc-lxd-dev",
            "binary_version": "2.0.11-0ubuntu1~16.04.4+esm3"
          },
          {
            "binary_name": "lxc2",
            "binary_version": "2.0.11-0ubuntu1~16.04.4+esm3"
          },
          {
            "binary_name": "lxd",
            "binary_version": "2.0.11-0ubuntu1~16.04.4+esm3"
          },
          {
            "binary_name": "lxd-client",
            "binary_version": "2.0.11-0ubuntu1~16.04.4+esm3"
          },
          {
            "binary_name": "lxd-tools",
            "binary_version": "2.0.11-0ubuntu1~16.04.4+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "lxd",
        "purl": "pkg:deb/ubuntu/lxd@2.0.11-0ubuntu1~16.04.4+esm3?arch=source\u0026distro=esm-infra-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.20-0ubuntu4",
        "0.21-0ubuntu3",
        "0.21-0ubuntu5",
        "0.22-0ubuntu1",
        "0.22-0ubuntu2",
        "0.23-0ubuntu1",
        "0.23-0ubuntu2",
        "0.23-0ubuntu3",
        "0.24-0ubuntu2",
        "0.24-0ubuntu3",
        "0.24-0ubuntu4",
        "0.25-0ubuntu1",
        "0.26-0ubuntu2",
        "0.26-0ubuntu3",
        "0.27-0ubuntu1",
        "0.27-0ubuntu2",
        "2.0.0~beta1-0ubuntu3",
        "2.0.0~beta1-0ubuntu4",
        "2.0.0~beta2-0ubuntu1",
        "2.0.0~beta2-0ubuntu2",
        "2.0.0~beta3-0ubuntu1",
        "2.0.0~beta3-0ubuntu2",
        "2.0.0~beta3-0ubuntu3",
        "2.0.0~beta3-0ubuntu4",
        "2.0.0~beta4-0ubuntu1",
        "2.0.0~beta4-0ubuntu2",
        "2.0.0~beta4-0ubuntu3",
        "2.0.0~beta4-0ubuntu4",
        "2.0.0~beta4-0ubuntu5",
        "2.0.0~beta4-0ubuntu6",
        "2.0.0~beta4-0ubuntu7",
        "2.0.0~rc1-0ubuntu1",
        "2.0.0~rc1-0ubuntu2",
        "2.0.0~rc1-0ubuntu3",
        "2.0.0~rc2-0ubuntu2",
        "2.0.0~rc2-0ubuntu3",
        "2.0.0~rc3-0ubuntu1",
        "2.0.0~rc3-0ubuntu2",
        "2.0.0~rc3-0ubuntu3",
        "2.0.0~rc3-0ubuntu4",
        "2.0.0~rc4-0ubuntu1",
        "2.0.0~rc5-0ubuntu1",
        "2.0.0~rc6-0ubuntu1",
        "2.0.0~rc6-0ubuntu2",
        "2.0.0~rc7-0ubuntu1",
        "2.0.0~rc7-0ubuntu2",
        "2.0.0~rc8-0ubuntu1",
        "2.0.0~rc8-0ubuntu2",
        "2.0.0~rc8-0ubuntu3",
        "2.0.0~rc8-0ubuntu5",
        "2.0.0~rc8-0ubuntu6",
        "2.0.0~rc8-0ubuntu7",
        "2.0.0~rc9-0ubuntu2",
        "2.0.0~rc9-0ubuntu3",
        "2.0.0~rc9-0ubuntu4",
        "2.0.0~rc9-0ubuntu5",
        "2.0.0-0ubuntu1",
        "2.0.0-0ubuntu2",
        "2.0.0-0ubuntu3",
        "2.0.0-0ubuntu4",
        "2.0.1-0ubuntu1~16.04.1",
        "2.0.2-0ubuntu1~16.04.1",
        "2.0.3-0ubuntu1~ubuntu16.04.2",
        "2.0.4-0ubuntu1~ubuntu16.04.1",
        "2.0.5-0ubuntu1~ubuntu16.04.1",
        "2.0.8-0ubuntu1~ubuntu16.04.1",
        "2.0.8-0ubuntu1~ubuntu16.04.2",
        "2.0.9-0ubuntu1~16.04.1",
        "2.0.9-0ubuntu1~16.04.2",
        "2.0.10-0ubuntu1~16.04.1",
        "2.0.10-0ubuntu1~16.04.2",
        "2.0.11-0ubuntu1~16.04.2",
        "2.0.11-0ubuntu1~16.04.4",
        "2.0.11-0ubuntu1~16.04.4+esm1",
        "2.0.11-0ubuntu1~16.04.4+esm2",
        "2.0.11-0ubuntu1~16.04.4+esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "lxd",
            "binary_version": "3.0.3-0ubuntu1~18.04.2+esm3"
          },
          {
            "binary_name": "lxd-client",
            "binary_version": "3.0.3-0ubuntu1~18.04.2+esm3"
          },
          {
            "binary_name": "lxd-tools",
            "binary_version": "3.0.3-0ubuntu1~18.04.2+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "lxd",
        "purl": "pkg:deb/ubuntu/lxd@3.0.3-0ubuntu1~18.04.2+esm3?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.18-0ubuntu6",
        "2.19-0ubuntu1",
        "2.20-0ubuntu3",
        "2.20-0ubuntu4",
        "2.21-0ubuntu1",
        "2.21-0ubuntu2",
        "2.21-0ubuntu3",
        "2.21-0ubuntu4",
        "3.0.0~beta2-0ubuntu3",
        "3.0.0~beta3-0ubuntu3",
        "3.0.0~beta5-0ubuntu2",
        "3.0.0~beta7-0ubuntu1",
        "3.0.0-0ubuntu1",
        "3.0.0-0ubuntu2",
        "3.0.0-0ubuntu3",
        "3.0.0-0ubuntu4",
        "3.0.1-0ubuntu1~18.04.1",
        "3.0.2-0ubuntu1~18.04.1",
        "3.0.3-0ubuntu1~18.04.1",
        "3.0.3-0ubuntu1~18.04.2",
        "3.0.3-0ubuntu1~18.04.2+esm1",
        "3.0.3-0ubuntu1~18.04.2+esm2",
        "3.0.3-0ubuntu1~18.04.2+esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "lxd",
            "binary_version": "1:0.10"
          },
          {
            "binary_name": "lxd-client",
            "binary_version": "1:0.10"
          },
          {
            "binary_name": "lxd-tools",
            "binary_version": "1:0.10"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "lxd",
        "purl": "pkg:deb/ubuntu/lxd@1:0.10?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:0.7",
        "1:0.8",
        "1:0.9",
        "1:0.10"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "golang-github-lxc-incus-dev",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
          },
          {
            "binary_name": "incus",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
          },
          {
            "binary_name": "incus-agent",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
          },
          {
            "binary_name": "incus-client",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
          },
          {
            "binary_name": "incus-migrate",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
          },
          {
            "binary_name": "incus-tools",
            "binary_version": "6.0.0-1ubuntu0.3+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "incus",
        "purl": "pkg:deb/ubuntu/incus@6.0.0-1ubuntu0.3+esm3?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.4-1ubuntu1",
        "0.5.1-1",
        "0.5.1-3",
        "0.6-1",
        "6.0.0-1",
        "6.0.0-1ubuntu0.1",
        "6.0.0-1ubuntu0.2",
        "6.0.0-1ubuntu0.2+esm1",
        "6.0.0-1ubuntu0.3",
        "6.0.0-1ubuntu0.3+esm1",
        "6.0.0-1ubuntu0.3+esm2",
        "6.0.0-1ubuntu0.3+esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "golang-github-lxc-incus-dev",
            "binary_version": "6.0.4-2"
          },
          {
            "binary_name": "incus",
            "binary_version": "6.0.4-2"
          },
          {
            "binary_name": "incus-agent",
            "binary_version": "6.0.4-2"
          },
          {
            "binary_name": "incus-base",
            "binary_version": "6.0.4-2"
          },
          {
            "binary_name": "incus-client",
            "binary_version": "6.0.4-2"
          },
          {
            "binary_name": "incus-extra",
            "binary_version": "6.0.4-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "incus",
        "purl": "pkg:deb/ubuntu/incus@6.0.4-2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "6.0.3-4",
        "6.0.4-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "golang-github-lxc-incus-dev",
            "binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
          },
          {
            "binary_name": "incus",
            "binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
          },
          {
            "binary_name": "incus-agent",
            "binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
          },
          {
            "binary_name": "incus-base",
            "binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
          },
          {
            "binary_name": "incus-client",
            "binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
          },
          {
            "binary_name": "incus-extra",
            "binary_version": "6.0.5-8ubuntu0.26.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "incus",
        "purl": "pkg:deb/ubuntu/incus@6.0.5-8ubuntu0.26.04.1~esm1?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "6.0.4-2",
        "6.0.5-8",
        "6.0.5-8ubuntu0.26.04.1~esm1"
      ]
    }
  ],
  "aliases": [],
  "details": "Incus is a system container and virtual machine manager. In versions 6.20.0 and below, a user with the ability to launch a container with a custom YAML configuration (e.g a member of the \u2018incus\u2019 group) can create an environment variable containing newlines, which can be used to add additional configuration items in the container\u2019s lxc.conf due to newline injection. This can allow adding arbitrary lifecycle hooks, ultimately resulting in arbitrary command execution on the host. Exploiting this issue on IncusOS requires a slight modification of the payload to change to a different writable directory for the validation step (e.g /tmp). This can be confirmed with a second container with /tmp mounted from the host (A privileged action for validation only). A fix is planned for versions 6.0.6 and 6.21.0, but they have not been released at the time of publication.",
  "id": "UBUNTU-CVE-2026-23953",
  "modified": "2026-07-02T16:11:56Z",
  "published": "2026-01-22T22:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-23953"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-23953"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lxc/incus/security/advisories/GHSA-x6jc-phwx-hp32"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lxc/incus/blob/HEAD/internal/server/instance/drivers/driver_lxc.go#L1081"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/user-attachments/files/24473682/environment_newline_injection.sh"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/user-attachments/files/24473685/environment_newline_injection.patch"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-23953"
  ]
}

CVE-2026-23953 (GCVE-0-2026-23953)

Vulnerability from cvelistv5 – Published: 2026-01-22 21:39 – Updated: 2026-01-26 21:00

Title

Incus container environment configuration newline injection

Summary

Severity

8.7 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-01-26 21:00 UTC

CWE

CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/lxc/incus/security/advisories/…	x_refsource_CONFIRM
https://github.com/lxc/incus/blob/HEAD/internal/s…	x_refsource_MISC
https://github.com/user-attachments/files/2447368…	x_refsource_MISC
https://github.com/user-attachments/files/2447368…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
lxc	incus	Affected: >= 6.1.0, <= 6.20.0 Affected: <= 6.0.5

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-23953",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-26T21:00:32.625486Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-26T21:00:46.311Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "incus",
          "vendor": "lxc",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 6.1.0, \u003c= 6.20.0"
            },
            {
              "status": "affected",
              "version": "\u003c= 6.0.5"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Incus is a system container and virtual machine manager. In versions 6.20.0 and below, a user with the ability to launch a container with a custom YAML configuration (e.g a member of the \u2018incus\u2019 group) can create an environment variable containing newlines, which can be used to add additional configuration items in the container\u2019s lxc.conf due to newline injection. This can allow adding arbitrary lifecycle hooks, ultimately resulting in arbitrary command execution on the host. Exploiting this issue on IncusOS requires a slight modification of the payload to change to a different writable directory for the validation step (e.g /tmp). This can be confirmed with a second container with /tmp mounted from the host (A privileged action for validation only). A fix is planned for versions 6.0.6\nand 6.21.0, but they have not been released at the time of publication."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "ADJACENT_NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-93",
              "description": "CWE-93: Improper Neutralization of CRLF Sequences (\u0027CRLF Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-22T21:39:41.015Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/lxc/incus/security/advisories/GHSA-x6jc-phwx-hp32",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/lxc/incus/security/advisories/GHSA-x6jc-phwx-hp32"
        },
        {
          "name": "https://github.com/lxc/incus/blob/HEAD/internal/server/instance/drivers/driver_lxc.go#L1081",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/lxc/incus/blob/HEAD/internal/server/instance/drivers/driver_lxc.go#L1081"
        },
        {
          "name": "https://github.com/user-attachments/files/24473682/environment_newline_injection.sh",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/user-attachments/files/24473682/environment_newline_injection.sh"
        },
        {
          "name": "https://github.com/user-attachments/files/24473685/environment_newline_injection.patch",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/user-attachments/files/24473685/environment_newline_injection.patch"
        }
      ],
      "source": {
        "advisory": "GHSA-x6jc-phwx-hp32",
        "discovery": "UNKNOWN"
      },
      "title": "Incus container environment configuration newline injection"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-23953",
    "datePublished": "2026-01-22T21:39:41.015Z",
    "dateReserved": "2026-01-19T14:49:06.312Z",
    "dateUpdated": "2026-01-26T21:00:46.311Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.