Vulnerability-Lookup

UBUNTU-CVE-2026-84042 (CVE-2026-84042)

Vulnerability from osv_ubuntu – Published: 2026-09-10 09:17 – Updated: 2026-10-17 09:54 – Source website

Details

A flaw was found in crun. When crun is built with libkrun and a container is started rootful with passt networking (krun.use_passt), crun can execute attacker-controlled payload from the container image with host root privileges. The issue is a regression in crun 1.29. It affects crun >= 1.29

Severity

7.8 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-84042	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-84042	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "crun",
            "binary_version": "0.12.1+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "crun",
        "purl": "pkg:deb/ubuntu/crun@0.12.1+dfsg-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
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              "introduced": "0"
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          "type": "ECOSYSTEM"
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      "versions": [
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        "0.10.6+dfsg-1",
        "0.11+dfsg-1",
        "0.12+dfsg-1",
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      ]
    },
    {
      "ecosystem_specific": {
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      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
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        "purl": "pkg:deb/ubuntu/crun@0.17+dfsg-1.1ubuntu0.1?arch=source\u0026distro=jammy"
      },
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      "versions": [
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        "0.17+dfsg-1.1",
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    },
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      "ecosystem_specific": {
        "binaries": [
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            "binary_name": "crun",
            "binary_version": "1.14.1-1"
          }
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      "package": {
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      "ecosystem_specific": {
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          {
            "binary_name": "crun",
            "binary_version": "1.21-1ubuntu3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "crun",
        "purl": "pkg:deb/ubuntu/crun@1.21-1ubuntu3?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
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      ],
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    },
    {
      "ecosystem_specific": {
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          {
            "binary_name": "crun",
            "binary_version": "1.21-1ubuntu3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "crun",
        "purl": "pkg:deb/ubuntu/crun@1.21-1ubuntu3?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.21-1ubuntu2",
        "1.21-1ubuntu3"
      ]
    }
  ],
  "aliases": [],
  "details": "A flaw was found in crun. When crun is built with libkrun and a container is started rootful with passt networking (krun.use_passt), crun can execute attacker-controlled payload from the container image with host root privileges. The issue is a regression in crun 1.29. It affects crun \u003e= 1.29",
  "id": "UBUNTU-CVE-2026-84042",
  "modified": "2026-10-17T09:54:12Z",
  "published": "2026-09-10T09:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-84042"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-84042"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-84042"
  ]
}

CVE-2026-84042 (GCVE-0-2026-84042)

Vulnerability from cvelistv5 – Published: 2026-09-10 08:24 – Updated: 2026-09-15 16:23

Title

Crun: crun: rootful krun with passt executes container payload as host root

Summary

Severity

7.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-10 17:34 UTC

CWE

CWE-269 - Improper Privilege Management

Assigner

redhat CNA under the redhat root

CNA scorecard B 82/100 over 1036 records in the last 180 days details

References

3 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-84042	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2531222	issue-trackingx_refsource_REDHAT
https://github.com/containers/crun/

Impacted products

5 products

Vendor	Product	Version
Red Hat	Red Hat Enterprise Linux 10	cpe:/o:redhat:enterprise_linux:10
Red Hat	Red Hat Enterprise Linux 8	cpe:/o:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	cpe:/o:redhat:enterprise_linux:9
Red Hat	Red Hat Hardened Images	cpe:/a:redhat:hummingbird:1
Red Hat	Red Hat OpenShift Container Platform 4	cpe:/a:redhat:openshift:4

Date Public

2026-09-10 00:00

Show details on NVD website

JSON

To clipboard

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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.

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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.
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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.

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