Vulnerability-Lookup

ubuntu-cve-2026-78408

Vulnerability from osv_ubuntu

Published

2026-09-03 00:00

Modified

2026-09-03 00:00

Summary

Details

The nsenter --join-cgroup option opens the target cgroup.procs file as root and leaves that file descriptor open across later namespace and credential changes and across execve(). Because the kernel checks later cgroup migrations using the credentials from the original open, a program run in an attacker-controlled target can inherit root's ability to move host processes between cgroups. After a privileged operator uses --join-cgroup against that target, an unprivileged user can migrate and terminate unrelated root processes.

Severity

7.9 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-78408	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-78408	REPORT
	https://github.com/util-linux/util-linux/security…	REPORT
	https://access.redhat.com/security/cve/CVE-2026-78408	REPORT
	https://bugzilla.redhat.com/show_bug.cgi?id=2522497	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bsdutils",
            "binary_version": "1:2.20.1-5.1ubuntu20.9"
          },
          {
            "binary_name": "libblkid1",
            "binary_version": "2.20.1-5.1ubuntu20.9"
          },
          {
            "binary_name": "libmount1",
            "binary_version": "2.20.1-5.1ubuntu20.9"
          },
          {
            "binary_name": "libuuid1",
            "binary_version": "2.20.1-5.1ubuntu20.9"
          },
          {
            "binary_name": "mount",
            "binary_version": "2.20.1-5.1ubuntu20.9"
          },
          {
            "binary_name": "util-linux",
            "binary_version": "2.20.1-5.1ubuntu20.9"
          },
          {
            "binary_name": "util-linux-locales",
            "binary_version": "2.20.1-5.1ubuntu20.9"
          },
          {
            "binary_name": "uuid-runtime",
            "binary_version": "2.20.1-5.1ubuntu20.9"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:14.04:LTS",
        "name": "util-linux",
        "purl": "pkg:deb/ubuntu/util-linux@2.20.1-5.1ubuntu20.9?arch=source\u0026distro=trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
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        "2.20.1-5.1ubuntu10",
        "2.20.1-5.1ubuntu11",
        "2.20.1-5.1ubuntu12",
        "2.20.1-5.1ubuntu13",
        "2.20.1-5.1ubuntu14",
        "2.20.1-5.1ubuntu15",
        "2.20.1-5.1ubuntu16",
        "2.20.1-5.1ubuntu17",
        "2.20.1-5.1ubuntu18",
        "2.20.1-5.1ubuntu19",
        "2.20.1-5.1ubuntu20",
        "2.20.1-5.1ubuntu20.1",
        "2.20.1-5.1ubuntu20.2",
        "2.20.1-5.1ubuntu20.3",
        "2.20.1-5.1ubuntu20.4",
        "2.20.1-5.1ubuntu20.6",
        "2.20.1-5.1ubuntu20.7",
        "2.20.1-5.1ubuntu20.9"
      ]
    },
    {
      "ecosystem_specific": {
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            "binary_name": "bsdutils",
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          },
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          },
          {
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          {
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          },
          {
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          },
          {
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          },
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          }
        ]
      },
      "package": {
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      },
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        "2.27.1-6ubuntu3.7",
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    },
    {
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          {
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          },
          {
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          },
          {
            "binary_name": "libuuid1",
            "binary_version": "2.31.1-0.4ubuntu3.7"
          },
          {
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          },
          {
            "binary_name": "rfkill",
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          },
          {
            "binary_name": "setpriv",
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          },
          {
            "binary_name": "util-linux",
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          },
          {
            "binary_name": "util-linux-locales",
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          },
          {
            "binary_name": "uuid-runtime",
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          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "util-linux",
        "purl": "pkg:deb/ubuntu/util-linux@2.31.1-0.4ubuntu3.7?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
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            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
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        "2.30.2-0.1ubuntu1",
        "2.30.2-0.1ubuntu2",
        "2.30.2-0.1ubuntu3",
        "2.31.1-0.4ubuntu2",
        "2.31.1-0.4ubuntu3",
        "2.31.1-0.4ubuntu3.1",
        "2.31.1-0.4ubuntu3.2",
        "2.31.1-0.4ubuntu3.3",
        "2.31.1-0.4ubuntu3.4",
        "2.31.1-0.4ubuntu3.5",
        "2.31.1-0.4ubuntu3.6",
        "2.31.1-0.4ubuntu3.7"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bsdutils",
            "binary_version": "1:2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "fdisk",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "libblkid1",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "libfdisk1",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "libmount1",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "libsmartcols1",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "libuuid1",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "mount",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "rfkill",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "util-linux",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "util-linux-locales",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          },
          {
            "binary_name": "uuid-runtime",
            "binary_version": "2.34-0.1ubuntu9.6+esm1"
          }
        ]
      },
      "package": {
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        "name": "util-linux",
        "purl": "pkg:deb/ubuntu/util-linux@2.34-0.1ubuntu9.6+esm1?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
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        "2.34-0.1ubuntu9.3",
        "2.34-0.1ubuntu9.4",
        "2.34-0.1ubuntu9.5",
        "2.34-0.1ubuntu9.6",
        "2.34-0.1ubuntu9.6+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bsdextrautils",
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          },
          {
            "binary_name": "bsdutils",
            "binary_version": "1:2.37.2-4ubuntu3.6"
          },
          {
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          },
          {
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          },
          {
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          },
          {
            "binary_name": "libmount1",
            "binary_version": "2.37.2-4ubuntu3.6"
          },
          {
            "binary_name": "libsmartcols1",
            "binary_version": "2.37.2-4ubuntu3.6"
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          {
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            "binary_version": "2.37.2-4ubuntu3.6"
          },
          {
            "binary_name": "mount",
            "binary_version": "2.37.2-4ubuntu3.6"
          },
          {
            "binary_name": "rfkill",
            "binary_version": "2.37.2-4ubuntu3.6"
          },
          {
            "binary_name": "util-linux",
            "binary_version": "2.37.2-4ubuntu3.6"
          },
          {
            "binary_name": "util-linux-locales",
            "binary_version": "2.37.2-4ubuntu3.6"
          },
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            "binary_name": "uuid-runtime",
            "binary_version": "2.37.2-4ubuntu3.6"
          }
        ]
      },
      "package": {
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        "name": "util-linux",
        "purl": "pkg:deb/ubuntu/util-linux@2.37.2-4ubuntu3.6?arch=source\u0026distro=jammy"
      },
      "ranges": [
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            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
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        "2.37.2-4ubuntu1",
        "2.37.2-4ubuntu2",
        "2.37.2-4ubuntu3",
        "2.37.2-4ubuntu3.3",
        "2.37.2-4ubuntu3.4",
        "2.37.2-4ubuntu3.5",
        "2.37.2-4ubuntu3.6"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bsdextrautils",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "bsdutils",
            "binary_version": "1:2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "eject",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "fdisk",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "libblkid1",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "libfdisk1",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "libmount1",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "libsmartcols1",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "libuuid1",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "mount",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "rfkill",
            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "util-linux",
            "binary_version": "2.39.3-9ubuntu6.6"
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          {
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            "binary_version": "2.39.3-9ubuntu6.6"
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            "binary_version": "2.39.3-9ubuntu6.6"
          },
          {
            "binary_name": "uuid-runtime",
            "binary_version": "2.39.3-9ubuntu6.6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "util-linux",
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      },
      "ranges": [
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        "2.39.2-6ubuntu1",
        "2.39.3-6ubuntu2",
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        "2.39.3-9ubuntu6",
        "2.39.3-9ubuntu6.1",
        "2.39.3-9ubuntu6.2",
        "2.39.3-9ubuntu6.3",
        "2.39.3-9ubuntu6.4",
        "2.39.3-9ubuntu6.5",
        "2.39.3-9ubuntu6.6"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bsdextrautils",
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          },
          {
            "binary_name": "bsdutils",
            "binary_version": "1:2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "eject",
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          },
          {
            "binary_name": "fdisk",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "lastlog2",
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          },
          {
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          },
          {
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          },
          {
            "binary_name": "liblastlog2-2",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "libmount1",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "libpam-lastlog2",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "libsmartcols1",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "libuuid1",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "login",
            "binary_version": "1:4.16.0-2+really2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "mount",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "rfkill",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "util-linux",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "util-linux-extra",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "util-linux-locales",
            "binary_version": "2.41.3-3ubuntu2.2"
          },
          {
            "binary_name": "uuid-runtime",
            "binary_version": "2.41.3-3ubuntu2.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "util-linux",
        "purl": "pkg:deb/ubuntu/util-linux@2.41.3-3ubuntu2.2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.41-4ubuntu4",
        "2.41.2-4ubuntu1",
        "2.41.2-4ubuntu2",
        "2.41.2-4ubuntu3",
        "2.41.3-3ubuntu1",
        "2.41.3-3ubuntu2",
        "2.41.3-3ubuntu2.2"
      ]
    }
  ],
  "aliases": [],
  "details": "The nsenter --join-cgroup option opens the target cgroup.procs file as root and leaves that file descriptor open across later namespace and credential changes and across execve(). Because the kernel checks later cgroup migrations using the credentials from the original open, a program run in an attacker-controlled target can inherit root\u0027s ability to move host processes between cgroups. After a privileged operator uses --join-cgroup against that target, an unprivileged user can migrate and terminate unrelated root processes.",
  "id": "UBUNTU-CVE-2026-78408",
  "modified": "2026-09-03T00:00:00Z",
  "published": "2026-09-03T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-78408"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-78408"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-55fx-f4gg-cfhj"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-78408"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2522497"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-78408"
  ]
}

CVE-2026-78408 (GCVE-0-2026-78408)

Vulnerability from cvelistv5 – Published: 2026-09-02 15:05 – Updated: 2026-09-05 13:06

Title

Util-linux: util-linux: nsenter --join-cgroup leaks root cgroup migration authority

Summary

Severity

7.9 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-04 02:32 UTC

CWE

CWE-775 - Missing Release of File Descriptor or Handle after Effective Lifetime

Assigner

redhat redhat root

References

5 references

URL	Tags
https://access.redhat.com/errata/RHSA-2026:63162	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-78408	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2522497	issue-trackingx_refsource_REDHAT
https://github.com/util-linux/util-linux/security…
http://www.openwall.com/lists/oss-security/2026/09/05/2

Impacted products

6 products

Vendor	Product	Version
Red Hat	Red Hat Hardened Images	Unaffected: 2.42.2-3.4.hum1 , < * (rpm) cpe:/a:redhat:hummingbird:1
Red Hat	Red Hat Enterprise Linux 10	cpe:/o:redhat:enterprise_linux:10
Red Hat	Red Hat Enterprise Linux 7	cpe:/o:redhat:enterprise_linux:7
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 OpenShift Container Platform 4	cpe:/a:redhat:openshift:4

Date Public

2026-09-02 00:00

Credits

Red Hat would like to thank Andreas Gabriel Berbescu (Independent Security Researcher) for reporting this issue.

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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.

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.