CVE-2023-38686

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2023-38686
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2023-08-04 16:15:00 UTC
Updated2023-08-10 19:30:00 UTC
DescriptionSydent 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.

Risk And Classification

Problem Types: CWE-295

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Matrix Sydent All All All All

References

ReferenceSourceLinkTags
Explicitly create an SSL context when emailing (#574) · matrix-org/sydent@1cd7483 · GitHub MISC github.com
Enable TLS hostname verification by default for SMTP/IMAP/FTP/POP/NNTP protocols · Issue #91826 · python/cpython · GitHub MISC github.com
PEP 476 – Enabling certificate verification by default for stdlib http clients | peps.python.org MISC peps.python.org
Sydent does not verify email server certificates · Advisory · matrix-org/sydent · GitHub MISC github.com
ssl — TLS/SSL wrapper for socket objects — Python 3.9.5 documentation MISC docs.python.org
Release v2.5.6 · matrix-org/sydent · GitHub MISC github.com
Explicitly create an SSL context when emailing by DMRobertson · Pull Request #574 · matrix-org/sydent · GitHub MISC github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
© CVE.report 2026 |

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report