Vulnerability-Lookup

CVE-2026-6970 (GCVE-0-2026-6970)

Vulnerability from cvelistv5 – Published: 2026-04-27 15:28 – Updated: 2026-04-27 16:17

Title

authd Denial of Service and Local Privilege Escalation

Summary

authd prior to version 0.6.4 contains a logic error in primary group ID assignment that can lead to local privilege escalation. When a user's primary group ID (GID) differs from their UID, either because the account was created with authd prior to version 0.5.4 or because the primary group was manually changed via the `authctl group set-gid` command, and the user's identity provider record is updated, authd incorrectly resets the user's primary group ID to their UID upon next login. This causes newly created files and directories to be owned by the wrong group, causing denial of service issues, and potentially granting unintended access to other local users and allowing local privilege escalation.

Severity

7.3 (High)


                        
                          CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-27 16:16 UTC

CWE

CWE-842 - Placement of user into incorrect group

Assigner

canonical CNA under the mitre root

CNA scorecard B 82/100 over 62 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/canonical/authd/security/advis…	vendor-advisory
https://github.com/canonical/authd/commit/154b428…	patch

Impacted products

1 product

Vendor	Product	Version	CPE status
Canonical	authd	Affected: 0.6.0 , < 0.6.4 (semver) Affected: 0.6.1 , < 0.6.1ubuntu0.1 (ubuntu-resolute)	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-6970

Vulnerability from fkie_nvd - Published: 2026-04-27 16:16 - Updated: 2026-10-26 22:10

Severity

7.3 (High) - CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Summary

References

	URL	Tags
	security@ubuntu.com	https://github.com/canonical/authd/commit/154b428305cb1a7a19c897626fefd09d6dde8b9f
	security@ubuntu.com	https://github.com/canonical/authd/security/advisories/GHSA-fg3j-5w9g-hmg7

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "platforms": [
            "Linux"
          ],
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    },
    {
      "lang": "es",
      "value": "authd anterior a la versi\u00f3n 0.6.4 contiene un error l\u00f3gico en la asignaci\u00f3n del ID de grupo primario que puede conducir a una escalada de privilegios local. Cuando el ID de grupo primario (GID) de un usuario difiere de su UID, ya sea porque la cuenta fue creada con authd anterior a la versi\u00f3n 0.5.4 o porque el grupo primario fue cambiado manualmente a trav\u00e9s del comando \u2019authctl group set-gid\u2019, y el registro del proveedor de identidad del usuario se actualiza, authd restablece incorrectamente el ID de grupo primario del usuario a su UID en el siguiente inicio de sesi\u00f3n. Esto provoca que los archivos y directorios reci\u00e9n creados sean propiedad del grupo incorrecto, causando problemas de denegaci\u00f3n de servicio, y potencialmente otorgando acceso no intencionado a otros usuarios locales y permitiendo la escalada de privilegios local."
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  ],
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          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security@ubuntu.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-6970",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-04-27T16:16:37.315715Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-04-27T16:16:46.300",
  "references": [
    {
      "source": "security@ubuntu.com",
      "url": "https://github.com/canonical/authd/commit/154b428305cb1a7a19c897626fefd09d6dde8b9f"
    },
    {
      "source": "security@ubuntu.com",
      "url": "https://github.com/canonical/authd/security/advisories/GHSA-fg3j-5w9g-hmg7"
    }
  ],
  "sourceIdentifier": "security@ubuntu.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-842"
        }
      ],
      "source": "security@ubuntu.com",
      "type": "Secondary"
    }
  ]
}

GHSA-FG3J-5W9G-HMG7

Vulnerability from github – Published: 2026-05-05 22:04 – Updated: 2026-05-05 22:04

Summary

authd: Primary group ID is incorrectly set to value of UID

Details

authd 0.6.0 contains a bug which can lead to an incorrect primary group ID.

It affects users whose primary group ID (i.e. the GID in the user record) differs from their UID. There are two ways which can lead to this:

The user was created with authd < 0.5.4 (released June 2025). Those users were created with UID != GID.
The primary group of the user was modified manually with the authctl utility that is shipped with authd (authctl group set-gid).

Another condition is that some user information must have changed in the identity provider (else the user record is not updated upon login). If that is the case, the next time an affected user logs in, authd will set their primary group ID to their UID.

This could lead to local privileges escalation. Also, files and directories created by those users will be owned by that incorrect primary group, which may grant other local users access to those files which they shouldn't have.

Users who are affected by the issue can run this script to fix the primary group ID of all authd users and the file ownership of files in the home directory created with the incorrect GID:

authd_users=$(getent passwd --service authd | cut -d: -f1)
for user in $authd_users; do
    OLD_GID=$(id -g "$user")
    GID=$(getent group "$user" | cut -d: -f3)
    if [ -z "$GID" ]; then
        echo "Warning: could not determine GID for $user, skipping" >&2
        continue
    fi
    if [ "$OLD_GID" = "$GID" ]; then
        continue  # user not affected
    fi
    USER_HOME=$(getent passwd "$user" | cut -d: -f6)
    echo "Fixing $user: resetting GID from $OLD_GID to $GID"
    sudo authctl group set-gid "$user" "$OLD_GID"
    sudo authctl group set-gid "$user" "$GID"
    sudo chown -R --from=":$OLD_GID" ":$GID" "$USER_HOME"
done

After applying the fix, affected users must log out and log back in for id, groups, and new file GID stamping to reflect the corrected primary group. You may also optionally terminate a user's active session with:

sudo loginctl terminate-user "$user"

If the users also own files outside their home directory, the ownership of those files might have to be updated as well.

Fixed by: https://github.com/canonical/authd/commit/154b428305cb1a7a19c897626fefd09d6dde8b9f

Severity

7.3 (High)


                  
                    CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/canonical/authd"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.6.0"
            },
            {
              "fixed": "0.6.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-6970"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-842"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-05T22:04:07Z",
    "nvd_published_at": "2026-04-27T16:16:46Z",
    "severity": "HIGH"
  },
  "details": "authd 0.6.0 contains [a bug](https://github.com/canonical/authd/issues/1482) which can lead to an incorrect primary group ID.\n\nIt affects users whose primary group ID (i.e. the GID in the user record) differs from their UID. There are two ways which can lead to this:\n\n1. The user was created with authd \u003c 0.5.4 (released June 2025). Those users were created with UID != GID.\n\n2. The primary group of the user was modified manually with the authctl utility that is shipped with authd (`authctl group set-gid`).\n\nAnother condition is that some user information must have changed in the identity provider (else the user record is not updated upon login). If that is the case, the next time an affected user logs in, authd will set their primary group ID to their UID.\n\nThis could lead to local privileges escalation. Also, files and directories created by those users will be owned by that incorrect primary group, which may grant other local users access to those files which they shouldn\u0027t have.\n\nUsers who are affected by the issue can run this script to fix the primary group ID of all authd users and the file ownership of files in the home directory created with the incorrect GID:\n\n```bash\nauthd_users=$(getent passwd --service authd | cut -d: -f1)\nfor user in $authd_users; do\n    OLD_GID=$(id -g \"$user\")\n    GID=$(getent group \"$user\" | cut -d: -f3)\n    if [ -z \"$GID\" ]; then\n        echo \"Warning: could not determine GID for $user, skipping\" \u003e\u00262\n        continue\n    fi\n    if [ \"$OLD_GID\" = \"$GID\" ]; then\n        continue  # user not affected\n    fi\n    USER_HOME=$(getent passwd \"$user\" | cut -d: -f6)\n    echo \"Fixing $user: resetting GID from $OLD_GID to $GID\"\n    sudo authctl group set-gid \"$user\" \"$OLD_GID\"\n    sudo authctl group set-gid \"$user\" \"$GID\"\n    sudo chown -R --from=\":$OLD_GID\" \":$GID\" \"$USER_HOME\"\ndone\n```\n\nAfter applying the fix, affected users must log out and log back in for `id`, `groups`, and new file GID stamping to reflect the corrected primary group. You may also optionally terminate a user\u0027s active session with:\n\n```bash\nsudo loginctl terminate-user \"$user\"\n```\n\nIf the users also own files outside their home directory, the ownership of those files might have to be updated as well.\n\nFixed by: https://github.com/canonical/authd/commit/154b428305cb1a7a19c897626fefd09d6dde8b9f",
  "id": "GHSA-fg3j-5w9g-hmg7",
  "modified": "2026-05-05T22:04:07Z",
  "published": "2026-05-05T22:04:07Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/canonical/authd/security/advisories/GHSA-fg3j-5w9g-hmg7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6970"
    },
    {
      "type": "WEB",
      "url": "https://github.com/canonical/authd/commit/154b428305cb1a7a19c897626fefd09d6dde8b9f"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/canonical/authd"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "authd: Primary group ID is incorrectly set to value of UID "
}

UBUNTU-CVE-2026-6970 (CVE-2026-6970)

Vulnerability from osv_ubuntu – Published: 2026-04-27 00:00 – Updated: 2026-05-20 15:24 – Source website

Details

authd prior to version 0.6.4 contains a logic error in primary group ID assignment that can lead to local privilege escalation. When a user's primary group ID (GID) differs from their UID, either because the account was created with authd prior to version 0.5.4 or because the primary group was manually changed via the authctl group set-gid command, and the user's identity provider record is updated, authd incorrectly resets the user's primary group ID to their UID upon next login. This causes newly created files and directories to be owned by the wrong group, causing denial of service issues, and potentially granting unintended access to other local users and allowing local privilege escalation.

Severity

7.3 (High)


                    
                      CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-6970	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-6970	REPORT
	https://ubuntu.com/security/notices/USN-8212-1	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "authd",
            "binary_version": "0.6.1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "authd",
        "purl": "pkg:deb/ubuntu/authd@0.6.1ubuntu0.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.6.1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.5.11",
        "0.6.1"
      ]
    }
  ],
  "aliases": [],
  "details": "authd prior to version 0.6.4 contains a logic error in primary group ID assignment that can lead to local privilege escalation. When a user\u0027s primary group ID (GID) differs from their UID, either because the account was created with authd prior to version 0.5.4 or because the primary group was manually changed via the `authctl group set-gid` command, and the user\u0027s identity provider record is updated, authd incorrectly resets the user\u0027s primary group ID to their UID upon next login. This causes newly created files and directories to be owned by the wrong group, causing denial of service issues, and potentially granting unintended access to other local users and allowing local privilege escalation.",
  "id": "UBUNTU-CVE-2026-6970",
  "modified": "2026-05-20T15:24:34Z",
  "published": "2026-04-27T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-6970"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-6970"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8212-1"
    }
  ],
  "related": [
    "USN-8212-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-6970"
  ]
}

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.

Vulnerability timeline

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How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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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.
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.

Action not permitted

CVE-2026-6970 (GCVE-0-2026-6970)

FKIE_CVE-2026-6970

GHSA-FG3J-5W9G-HMG7

UBUNTU-CVE-2026-6970 (CVE-2026-6970)

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