UBUNTU-CVE-2026-102631

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/CVE-2026-102631
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102631.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-102631
Upstream
Published
2026-10-15T16:42:00Z
Modified
2026-10-17T12:59:44Z
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
  • Ubuntu - medium
Summary
[none]
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.

References

Affected packages

Ubuntu:26.04:LTS / authd

Package

Name
authd
Purl
pkg:deb/ubuntu/authd?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.5.11
0.6.1
0.6.1ubuntu0.1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "authd",
            "binary_version":  "0.6.1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102631.json"