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🛡️ CVE-2023-32682 — matrix-synapse

🟡 CVSS 5.4 — Medium ✅ No Known Exploit CWE-287 NVD
5.4
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Synapse has improper checks for deactivated users during login

Impact

It may be possible for a deactivated user to login when using uncommon configurations.

This only applies if any of the following are true:

  • [JSON Web Tokens are enabled for login](https://matrix-org.github.io/synapse/latest/jwt.html) via the jwt_config.enabled configuration setting
  • The [local password database is enabled](https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#password_config) via the password_config.enabled and password_config.localdb_enabled configuration settings *and* a user's password is [updated via an admin API](https://matrix-org.github.io/synapse/latest/admin_api/user_admin_api.html#create-or-modify-account) after a user is deactivated.

Note that the local password database is enabled by default, but it is uncommon to set a user's password after they've been deactivated.

Installations that are configured to only allow login via Single Sign-On (SSO) via CAS, SAML or OpenID Connect (OIDC); or via an external password provider (e.g. LDAP) are not affected.

Patches

  • If using JSON Web Token logins: #15624
  • For other users: #15634

Workarounds

If not using JSON Web Tokens, ensure that deactivated users do not have a password set. This list of users can be queried from PostgreSQL:

```sql

SELECT name FROM users WHERE password_hash IS NOT NULL AND deactivated = 1;

```

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity low, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: None.

Weakness class

CVE-2023-32682 is classified as CWE-287: Improper Authentication. The identity of the caller is not established correctly, so an attacker can act as another user.

Affected software

CVE-2023-32682 is recorded against 2 packages.

  • matrix-synapse (fixed in 1.85.0)
  • synapse (fixed in 1.85.0)

Timeline and source

Published on 6 June 2023 and last revised on 24 September 2024. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com (Fix)
matrix-org.github.io (Web)
github.com (Fix)
matrix-org.github.io (Web)
matrix-org.github.io (Web)
github.com (Fix)

Other advisories for this package

matrix-synapse has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-287: Improper Authentication) in other software:

CVE-2023-32682 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Medium
CVSS Score 5.4
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
CWE CWE-287
Public Exploit ✅ No
Source NVD
Published 2023-06-06
Updated 2026-08-20
Modified 2024-09-24

Affected Packages

Software From version Fixed in
matrix-synapse — 1.85.0
synapse — 1.85.0

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