CVE-2026-102631

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Source

https://cve.org/CVERecord?id=CVE-2026-102631

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-102631.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-102631

Published

2026-10-15T16:42:19Z

Modified

2026-10-16T02:47:41Z

Severity

5.9 (Medium) CVSS_V4 - 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 CVSS Calculator

Summary

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

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.

Database specific

{
    "cna_assigner":  "canonical",
    "cwe_ids":  [
        "CWE-287"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102631.json",
    "unresolved_ranges":  [
        {
            "extracted_events":  [
                {
                    "introduced":  "0.1"
                },
                {
                    "fixed":  "0.7.1~ubuntu24.04.1"
                },
                {
                    "introduced":  "0.1"
                },
                {
                    "fixed":  "0.7.1~ubuntu26.04"
                }
            ],
            "source":  "AFFECTED_FIELD"
        }
    ]
}

References

Affected packages

Git / github.com/canonical/authd

Affected ranges

Type

GIT

Repo

https://github.com/canonical/authd

Events

Introduced

746bcfc293877031107b5c7b6e211d2f25009efa

Fixed

cd1a2113f8f57ab04b4c364467a8625866267245

Database specific

Show details

{
    "extracted_events":  [
        {
            "introduced":  "0.1"
        },
        {
            "fixed":  "0.7.1"
        }
    ],
    "source":  "AFFECTED_FIELD"
}

Affected versions

0.*

0.3.5

broker-0.*

broker-0.4.0

v0.*

v0.1

v0.2.1

v0.3.2

v0.3.3

v0.3.5

v0.3.6

v0.3.7

v0.6.1

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-102631.json"