ubuntu-cve-2026-34090
Vulnerability from osv_ubuntu
Published
2026-05-11 16:17
Modified
2026-05-20 15:27
Summary
Details

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation CheckUser. This issue affects CheckUser: from 1.45.0 before 1.45.2.

Severity
4.8 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/R:U
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mediawiki",
            "binary_version": "1:1.27.4-3"
          },
          {
            "binary_name": "mediawiki-classes",
            "binary_version": "1:1.27.4-3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "mediawiki",
        "purl": "pkg:deb/ubuntu/mediawiki@1:1.27.4-3?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.27.3-1",
        "1:1.27.4-1",
        "1:1.27.4-2",
        "1:1.27.4-3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mediawiki",
            "binary_version": "1:1.31.7-1"
          },
          {
            "binary_name": "mediawiki-classes",
            "binary_version": "1:1.31.7-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "mediawiki",
        "purl": "pkg:deb/ubuntu/mediawiki@1:1.31.7-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.31.2-1ubuntu1",
        "1:1.31.5-1",
        "1:1.31.5-1ubuntu1",
        "1:1.31.5-2",
        "1:1.31.5-3",
        "1:1.31.5-3ubuntu1",
        "1:1.31.6-1",
        "1:1.31.7-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mediawiki",
            "binary_version": "1:1.35.6-1"
          },
          {
            "binary_name": "mediawiki-classes",
            "binary_version": "1:1.35.6-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "mediawiki",
        "purl": "pkg:deb/ubuntu/mediawiki@1:1.35.6-1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.35.3-1",
        "1:1.35.4-1",
        "1:1.35.5-1",
        "1:1.35.5-1ubuntu1",
        "1:1.35.5-1ubuntu2",
        "1:1.35.5-1ubuntu3",
        "1:1.35.6-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mediawiki",
            "binary_version": "1:1.39.7-1"
          },
          {
            "binary_name": "mediawiki-classes",
            "binary_version": "1:1.39.7-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "mediawiki",
        "purl": "pkg:deb/ubuntu/mediawiki@1:1.39.7-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.39.4-2",
        "1:1.39.5-1",
        "1:1.39.6-1",
        "1:1.39.7-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mediawiki",
            "binary_version": "1:1.43.3+dfsg-1"
          },
          {
            "binary_name": "mediawiki-classes",
            "binary_version": "1:1.43.3+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "mediawiki",
        "purl": "pkg:deb/ubuntu/mediawiki@1:1.43.3+dfsg-1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.43.1+dfsg-1",
        "1:1.43.1+dfsg-2",
        "1:1.43.3+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "mediawiki",
            "binary_version": "1:1.43.8+dfsg-2"
          },
          {
            "binary_name": "mediawiki-classes",
            "binary_version": "1:1.43.8+dfsg-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "mediawiki",
        "purl": "pkg:deb/ubuntu/mediawiki@1:1.43.8+dfsg-2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.43.3+dfsg-1",
        "1:1.43.5+dfsg-1",
        "1:1.43.6+dfsg-2",
        "1:1.43.8+dfsg-1",
        "1:1.43.8+dfsg-2"
      ]
    }
  ],
  "aliases": [],
  "details": "Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation CheckUser. This issue affects CheckUser: from 1.45.0 before 1.45.2.",
  "id": "UBUNTU-CVE-2026-34090",
  "modified": "2026-05-20T15:27:23Z",
  "published": "2026-05-11T16:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34090"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34090"
    },
    {
      "type": "REPORT",
      "url": "https://phabricator.wikimedia.org/T411366"
    },
    {
      "type": "REPORT",
      "url": "https://gerrit.wikimedia.org/r/c/mediawiki/extensions/CheckUser/+/1240641"
    },
    {
      "type": "REPORT",
      "url": "https://lists.wikimedia.org/hyperkitty/list/wikitech-l@lists.wikimedia.org/thread/DIBLSBHISKX6NFRUFNOGZRVW42E7R2QP/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/R:U",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-34090"
  ],
  "withdrawn": "2026-05-26T07:19:42Z"
}



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Sightings

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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.