CVE-2023-38686
This makes Sydent's emails vulnerable to interception via a man-in-the-middle (MITM) attack.
Does this matter?
Lower severity and a low EPSS score (0.27%). Track it; it rarely justifies an emergency change on its own.
Description
Sydent is an identity server for the Matrix communications protocol. Prior to version 2.5.6, if configured to send emails using TLS, Sydent does not verify SMTP servers' certificates. This makes Sydent's emails vulnerable to interception via a man-in-the-middle (MITM) attack. Attackers with privileged access to the network can intercept room invitations and address confirmation emails. This is patched in Sydent 2.5.6. When patching, make sure that Sydent trusts the certificate of the server it is connecting to. This should happen automatically when using properly issued certificates. Those who use self-signed certificates should make sure to copy their Certification Authority certificate, or their self signed certificate if using only one, to the trust store of your operating system. As a workaround, one can ensure Sydent's emails fail to send by setting the configured SMTP server to a loopback or non-routable address under one's control which does not have a listening SMTP server.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.27% probability · 18th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-295
- Affected
- matrix/sydent
- Source
- security-advisories@github.com
References
- https://docs.python.org/3/library/ssl.html?highlight=ssl#security-considerationsTechnical Description
- https://github.com/matrix-org/sydent/commit/1cd748307c6b168b66154e6c4db715d4b9551261Patch
- https://github.com/matrix-org/sydent/pull/574Issue Tracking, Patch
- https://github.com/matrix-org/sydent/releases/tag/v2.5.6Release Notes
- https://github.com/matrix-org/sydent/security/advisories/GHSA-p6hw-wm59-3g5gVendor Advisory
- https://github.com/python/cpython/issues/91826Issue Tracking
- https://peps.python.org/pep-0476/Third Party Advisory
- https://docs.python.org/3/library/ssl.html?highlight=ssl#security-considerationsTechnical Description
- https://github.com/matrix-org/sydent/commit/1cd748307c6b168b66154e6c4db715d4b9551261Patch
- https://github.com/matrix-org/sydent/pull/574Issue Tracking, Patch
- https://github.com/matrix-org/sydent/releases/tag/v2.5.6Release Notes
- https://github.com/matrix-org/sydent/security/advisories/GHSA-p6hw-wm59-3g5gVendor Advisory
- https://github.com/python/cpython/issues/91826Issue Tracking
- https://peps.python.org/pep-0476/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.