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TI-2026-74836 Aliases CVE-2026-102631

Account takeover in authd after IdP email reassignment

Priority LOW 25CWE-287Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
Present
Impact type
Security bypass
Confidentiality · integrity · availability
High · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-287.

Summary

Canonical authd is affected before 0.7.1, before 0.7.1~ubuntu24.04.1 and before 0.7.1~ubuntu26.04. Identity matching falls back to the username when the provider ID is unknown and accepts a conflicting provider ID (CWE-287). A reassigned email address lets the new account inherit the previous user's local UID and home directory on its next login. A local attacker with no privileges can then read and modify that user's files, including SSH keys and cloud API tokens.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00112 1st percentileScored 2026-11-07
Fix Fixed authd (Canonical): 0.7.1, 0.7.1~ubuntu24.04.1, 0.7.1~ubuntu26.04

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Canonicalauthd0.1 to before 0.7.1; 0.1 to before 0.7.1~ubuntu24.04.1; 0.1 to before 0.7.1~ubuntu26.040.7.1, 0.7.1~ubuntu24.04.1, 0.7.1~ubuntu26.04Patch availableCNA
  • authd VendorCanonical Affected 0.1 to before 0.7.1; 0.1 to before 0.7.1~ubuntu24.04.1; 0.1 to before 0.7.1~ubuntu26.04 Fixed in 0.7.1, 0.7.1~ubuntu24.04.1, 0.7.1~ubuntu26.04 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:canonical:authd:*:*:*:*:*:*:*:*——Canonical
  • cpe:2.3:a:canonical:authd:*:*:*:*:*:*:*:* Versions — — ·Canonical

Remediation

Upgrade Canonical authd to 0.7.1, 0.7.1~ubuntu24.04.1 or 0.7.1~ubuntu26.04, which fix the flaw. Until the update is applied, lock or delete the previous user's local authd account when the corresponding identity provider account is removed.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA authd (Canonical) Fixed in 0.7.1, 0.7.1~ubuntu24.04.1, 0.7.1~ubuntu26.04

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-16 Threatist record created from CVE-2026-102631
  2. 2026-10-16 Priority changed: MEDIUM → LOW
  3. 2026-10-18 CISA SSVC decision points changed
  4. 2026-11-06 Affected versions changed · Red Hat
  5. 2026-11-06 CVSS score added · Red Hat

References

Patch 1

Advisory 1

Other 1

  • TI-2020-09349 An issue was discovered in SaltStack Salt before 2019.2.4 and 3000 before 3000.2. KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-05854 smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other… KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-01431 Netlogon Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 10.0
  • TI-2019-12627 Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than… KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-07471 OS command injection in exim KEVCVSS 3.1CRITICAL 9.8
See all 4301 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences