Security Disclosure Policy

Matrix.org greatly appreciates investigative work into security vulnerabilities carried out by well-intentioned, ethical security researchers. We follow the practice of responsible disclosure in order to best protect Matrix’s user-base from the impact of security issues. On our side, this means:

• We will respond to security incidents as a priority.
• We will fix the issue as soon as is practical, keeping in mind that not all risks are created equal.
• We will always transparently let the community know about any incident that affects them.

If you have found a security vulnerability in Matrix, we ask that you disclose it responsibly by emailing [email protected]. Please do not discuss potential vulnerabilities in public without validating with us first.

On receipt the security team will:

• Review the report, verify the vulnerability and respond with confirmation and/or further information requests; we typically reply within 24 hours.
• Once the reported security bug has been addressed we will notify the Researcher, who is then welcome to optionally disclose publicly.

The Matrix.org Foundation does not ordinarily provide bug bounties, though organisations building on top of Matrix may do so in future.

We maintain a Hall of Fame to recognise those who have responsibly disclosed security issues to us in the past.

Hall of Fame

2021-05-21 - Element Android - Aaron Raimist and an anonymous security researcher
Discovered that Element Android was disclosing the filename of end-to-end encrypted attachments to the homeserver. Fixed in Element Android 1.1.8.
2021-03-01 - Dendrite - Graham Leach-Krouse
Authentication bypass in SQLite deployments. Fixed in Dendrite v0.3.11.
2021-02-16 - Matrix React SDK - Guilherme Keerok
User content sandbox could be tricked into opening arbitrary documents (CVE-2021-21320). Fixed in matrix-react-sdk 3.15.0.
2021-01-18 - Synapse - Michaël Scherer
IP blacklist bypass via transitional IPv6 addresses on dual-stack networks (CVE-2021-21392). Fixed in Synapse 1.28.0.
2021-01-07 - Element iOS - Andrea Spacca
Element iOS crash via an invalid content payload. Fixed in Element iOS 1.1.4.
2020-11-17 - Synapse - Michaël Scherer
Denial of service attack via .well-known lookups (CVE-2021-21274). Fixed in Synapse 1.25.0.
2020-11-17 - Synapse - Michaël Scherer
IP blacklist bypass via redirects on some federation and push requests (CVE-2021-21273). Fixed in Synapse 1.25.0.
2020-09-20 - Synapse - Denis Kasak
HTML injection in login fallback endpoints could be used for a Cross-site-scripting attack (CVE-2020-26891). Fixed in Synapse 1.21.0.
2020-09-09 - New Vector Infrastructure - Pritam Mukherjee
Misconfigured X-Frame in New Vector internal infrastructure could lead to Clickjacking
2020-08-14 - Element - awesome-michael - Awesome Technologies
An issue where encrypted state events could break incoming call handling. Fixed in Element 1.7.5
2020-07-29 - Element - TR_SLimey
An issue where Element Android was leaking PII. Fixed in Element Android 1.0.5
2020-07-20 - Element - SakiiR
An issue where an unexpected language ID in a code block could cause Element to crash. Fixed in Element 1.7.3
2020-07-14 - Synapse - Denis Kasak
Invalid JSON could become part of the room state, acting as a denial of service vector (CVE-2020-26890). Fixed in Synapse 1.20.0. Disclosed 2020-11-23.
2020-07-02 - Synapse - Quentin Gliech
A clickjacking vulnerability in the single-sign-on flow in Synapse. Fixed in Synapse 1.15.2.
2020-06-18 - Element - Sorunome
An issue where replying to a specially formatted message would make it seem like the replier said something they did not. Fixed in Element 1.7.3
2020-05-10 - Matrix React SDK - Quentin Gliech
A CSRF attack leading to potential unauthorised access to accounts on servers using single-sign-on flows. Fixed as part of matrix-react-sdk#4685, released in Riot/Web 1.6.3.
2020-05-03 - e2e spec - David Wong
A vulnerability in the SAS verification protocol failing to bind the ephemeral public keys. Fixed in MSC2630, which lists the fixed client versions.
2020-03-03 - Synapse - Rhys Davies
An open redirect vulnerability affecting single sign-on flows. Fixed in Synapse 1.11.1
2019-05-02 - sydent - Enguerran Gillier
HTML injection in email invites. A malicious 3rd party invite could inject unescaped HTML into the email template. Fixed in Sydent 1.0.3
2019-05-02 - synapse - Enguerran Gillier
SSRF in the URL preview API, which did not blacklist access to 0.0.0.0/32 or ::/128 by default. Fixed in Synapse 0.99.3.1
2019-05-02 - synapse - Enguerran Gillier
Insecure pseudo-random number generator in synapse meant that an attacker might be able to predict random values. Fixed in Synapse 0.99.3.1
2019-05-02 - sydent - Enguerran Gillier
Insecure pseudo-random number generator in sydent meant that an attacker could predict authentication tokens. Fixed in Sydent 1.0.3
2019-04-22 - Riot/Android - Julien Thomas - Protektoid Project
Obsolete and buggy ContentProvider in Riot/Android meant that a malicious local app could compromise account data. Mitigated here.
2019-04-20 - Sydent - fs0c131y
Sydent sesssion ids were predictable, meaning it was possible to infer the total number of validations and also check if an address had been validated. Mitigated here.
2019-04-18 - Sydent - fs0c131y
An email validation exploit in Sydent. For more details see here and CVE-2019-11340.
2019-04-09 - Infrastructure - Jaikey Sarraf
Identified a unpatched RCE vulnerability in Matrix.org's public-facing Jenkins. It transpired the vulnerability had been exploited by an attacker.
2018-12-06 - Synapse - Brian Hyde
XSS exploit allowing a malicious SWF uploaded to Riot via Firefox to run arbitrary code in the domain of the content repository. Mitigated here.
2018-02-19 - Matrix React SDK - rugk
Origin check of ScalarMessaging postmessage API was insufficient. Mitigated here.

If you think you should be on the list, apologies if we missed you, please mail us at [email protected]