USN-8833-1 (UBUNTU-CVE-2026-18917)

Vulnerability from osv_ubuntu – Published: 2026-09-28 11:57 – Updated: 2026-09-28 11:57 – Source website
VLAI
Summary
libvirt-hwe vulnerabilities
Details

It was discovered that libvirt did not properly validate newline characters in DNS TXT record values and SRV record attributes in its virtual network driver. A local attacker with permission to define virtual networks could possibly use this issue to inject arbitrary dnsmasq configuration directives, leading to arbitrary command execution as root. (CVE-2026-61477)

It was discovered that libvirt did not properly handle errors during XML context parsing. An attacker could possibly use this issue to cause libvirt to crash, resulting in a denial of service. (CVE-2026-61478)

He Wei discovered that libvirt had a symlink-following vulnerability in the file ownership change function used for virtual TPM state directories. A local attacker running as the swtpm user could possibly use this issue to cause libvirt to change the ownership of an arbitrary file, leading to privilege escalation. (CVE-2026-63622)

It was discovered that libvirt created storage volume images with overly permissive permissions during clone or convert operations. A local attacker could possibly use this issue to read guest disk contents, resulting in information disclosure. (CVE-2026-63623)

It was discovered that libvirt had an integer overflow in the NodeGetFreePages RPC handler. A local attacker could possibly use this issue to cause libvirt to crash or execute arbitrary code. (CVE-2026-18917)

It was discovered that libvirt had a symlink-following flaw in the virtual TPM emulator setup function. A local attacker with access to the swtpm account could possibly use this issue to cause libvirt to change the ownership of an arbitrary file, leading to privilege escalation. (CVE-2026-77159)

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-18917",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-61477",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-61478",
              "severity": [
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-63622",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-63623",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-77159",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:26.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libnss-libvirt-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-clients-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-clients-qemu-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-common-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-common-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-config-network-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-config-nwfilter-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-interface-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-lxc-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-network-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-nodedev-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-nwfilter-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-qemu-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-secret-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-disk-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-gluster-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-iscsi-direct-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-iscsi-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-logical-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-mpath-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-rbd-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-scsi-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-storage-zfs-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-vbox-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-driver-xen-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-lock-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-log-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-plugin-lockd-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-plugin-sanlock-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-system-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-system-systemd-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-daemon-system-sysv-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-dev-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-doc-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-l10n-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-login-shell-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-sanlock-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-ssh-proxy-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt-wireshark-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          },
          {
            "binary_name": "libvirt0-hwe",
            "binary_version": "12.0.0-1ubuntu5.5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libvirt-hwe",
        "purl": "pkg:deb/ubuntu/libvirt-hwe@12.0.0-1ubuntu5.5?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "12.0.0-1ubuntu5.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "12.0.0-1ubuntu5",
        "12.0.0-1ubuntu5.1",
        "12.0.0-1ubuntu5.2",
        "12.0.0-1ubuntu5.3"
      ]
    }
  ],
  "aliases": [],
  "details": "It was discovered that libvirt did not properly validate newline characters\nin DNS TXT record values and SRV record attributes in its virtual network\ndriver. A local attacker with permission to define virtual networks could\npossibly use this issue to inject arbitrary dnsmasq configuration\ndirectives, leading to arbitrary command execution as root.\n(CVE-2026-61477)\n\nIt was discovered that libvirt did not properly handle errors during XML\ncontext parsing. An attacker could possibly use this issue to cause libvirt\nto crash, resulting in a denial of service. (CVE-2026-61478)\n\nHe Wei discovered that libvirt had a symlink-following vulnerability in the\nfile ownership change function used for virtual TPM state directories. A\nlocal attacker running as the swtpm user could possibly use this issue to\ncause libvirt to change the ownership of an arbitrary file, leading to\nprivilege escalation. (CVE-2026-63622)\n\nIt was discovered that libvirt created storage volume images with overly\npermissive permissions during clone or convert operations. A local attacker\ncould possibly use this issue to read guest disk contents, resulting in\ninformation disclosure. (CVE-2026-63623)\n\nIt was discovered that libvirt had an integer overflow in the\nNodeGetFreePages RPC handler. A local attacker could possibly use this\nissue to cause libvirt to crash or execute arbitrary code.\n(CVE-2026-18917)\n\nIt was discovered that libvirt had a symlink-following flaw in the virtual\nTPM emulator setup function. A local attacker with access to the swtpm\naccount could possibly use this issue to cause libvirt to change the\nownership of an arbitrary file, leading to privilege escalation.\n(CVE-2026-77159)",
  "id": "USN-8833-1",
  "modified": "2026-09-28T11:57:56Z",
  "published": "2026-09-28T11:57:56Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8833-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-18917"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-61477"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-61478"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-63622"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-63623"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-77159"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "libvirt-hwe vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2026-18917",
    "UBUNTU-CVE-2026-61477",
    "UBUNTU-CVE-2026-61478",
    "UBUNTU-CVE-2026-63622",
    "UBUNTU-CVE-2026-63623",
    "UBUNTU-CVE-2026-77159"
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



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.