Vulnerability-Lookup

GHSA-92HM-XX6P-HCH9

Vulnerability from github – Published: 2026-10-15 18:32 – Updated: 2026-10-15 18:32

Details

In authd before 0.7.1, the user identity matching in UpdateUser (internal/users/manager.go) resolves an incoming login by the broker-scoped provider ID, but falls back to matching the username when the provider ID does not belong to any known user, and does not reject a conflicting non-empty provider ID. If an identity provider reassigns an email address, which authd uses as the username, to a new account, the new account inherits the previous user's local UID and home directory on its next login. This allows the new user to access and modify files belonging to the previous user, including credentials such as SSH keys and cloud API tokens, and silently rebinds the local account record to the new identity. As a mitigation, administrators should lock or delete the previous user's local authd account when the corresponding IdP account is removed.

Severity

5.9 (Medium)


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

Show details on source website

JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-102631"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-15T17:17:10Z",
    "severity": "MODERATE"
  },
  "details": "In authd before 0.7.1, the user identity matching in UpdateUser (internal/users/manager.go) resolves an incoming login by the broker-scoped provider ID, but falls back to matching the username when the provider ID does not belong to any known user, and does not reject a conflicting non-empty provider ID. If an identity provider reassigns an email address, which authd uses as the username, to a new account, the new account inherits the previous user\u0027s local UID and home directory on its next login. This allows the new user to access and modify files belonging to the previous user, including credentials such as SSH keys and cloud API tokens, and silently rebinds the local account record to the new identity. As a mitigation, administrators should lock or delete the previous user\u0027s local authd account when the corresponding IdP account is removed.",
  "id": "GHSA-92hm-xx6p-hch9",
  "modified": "2026-10-15T18:32:42Z",
  "published": "2026-10-15T18:32:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102631"
    },
    {
      "type": "WEB",
      "url": "https://github.com/canonical/authd/pull/2067"
    },
    {
      "type": "WEB",
      "url": "https://bugs.launchpad.net/ubuntu/+source/authd/+bug/2168531"
    },
    {
      "type": "WEB",
      "url": "https://ubuntu.com/security/CVE-2026-102631"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-102631 (GCVE-0-2026-102631)

Vulnerability from cvelistv5 – Published: 2026-10-15 16:42 – Updated: 2026-10-16 20:16

Title

authd: Account takeover via username fallback in identity matching after IdP email reassignment

Summary

Severity

5.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-16 20:16 UTC

CWE

CWE-287 - Improper Authentication

Assigner

canonical CNA under the mitre root

CNA scorecard B 80/100 over 102 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/canonical/authd/pull/2067	patch
https://bugs.launchpad.net/ubuntu/+source/authd/+…	issue-tracking
https://ubuntu.com/security/CVE-2026-102631	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
Canonical	authd	Affected: 0.1 , < 0.7.1 (custom) Affected: 0.1 , < 0.7.1~ubuntu24.04.1 (custom) Affected: 0.1 , < 0.7.1~ubuntu26.04 (custom)

Credits

Ali Mashally Adrian Dombeck

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-102631",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-16T20:16:37.623815Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-16T20:16:49.275Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageName": "authd",
          "platforms": [
            "Linux"
          ],
          "product": "authd",
          "repo": "https://github.com/canonical/authd",
          "vendor": "Canonical",
          "versions": [
            {
              "lessThan": "0.7.1",
              "status": "affected",
              "version": "0.1",
              "versionType": "custom"
            },
            {
              "lessThan": "0.7.1~ubuntu24.04.1",
              "status": "affected",
              "version": "0.1",
              "versionType": "custom"
            },
            {
              "lessThan": "0.7.1~ubuntu26.04",
              "status": "affected",
              "version": "0.1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Ali Mashally"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Adrian Dombeck"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In authd before 0.7.1, the user identity matching in UpdateUser (internal/users/manager.go) resolves an incoming login by the broker-scoped provider ID, but falls back to matching the username when the provider ID does not belong to any known user, and does not reject a conflicting non-empty provider ID. If an identity provider reassigns an email address, which authd uses as the username, to a new account, the new account inherits the previous user\u0027s local UID and home directory on its next login. This allows the new user to access and modify files belonging to the previous user, including credentials such as SSH keys and cloud API tokens, and silently rebinds the local account record to the new identity. As a mitigation, administrators should lock or delete the previous user\u0027s local authd account when the corresponding IdP account is removed."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-287",
              "description": "CWE-287 Improper Authentication",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-15T16:42:19.368Z",
        "orgId": "cc1ad9ee-3454-478d-9317-d3e869d708bc",
        "shortName": "canonical"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/canonical/authd/pull/2067"
        },
        {
          "tags": [
            "issue-tracking"
          ],
          "url": "https://bugs.launchpad.net/ubuntu/+source/authd/+bug/2168531"
        },
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://ubuntu.com/security/CVE-2026-102631"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "authd: Account takeover via username fallback in identity matching after IdP email reassignment",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "cc1ad9ee-3454-478d-9317-d3e869d708bc",
    "assignerShortName": "canonical",
    "cveId": "CVE-2026-102631",
    "datePublished": "2026-10-15T16:42:19.368Z",
    "dateReserved": "2026-09-29T15:27:33.452Z",
    "dateUpdated": "2026-10-16T20:16:49.275Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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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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.

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