CVE-2020-26890: Input Validation
First published: Tue Nov 24 2020(Updated: )
Matrix Synapse before 1.20.0 erroneously permits non-standard NaN, Infinity, and -Infinity JSON values in fields of m.room.member events, allowing remote attackers to execute a denial of service attack against the federation and common Matrix clients. If such a malformed event is accepted into the room's state, the impact is long-lasting and is not fixed by an upgrade to a newer version, requiring the event to be manually redacted instead. Since events are replicated to servers of other room members, the impact is not constrained to the server of the event sender.
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Matrix Synapse | <1.20.0 | |
| Fedoraproject Fedora | =32 | |
| Fedoraproject Fedora | =33 |
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Reference Links
- https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ/
Frequently Asked Questions
What is the vulnerability ID?
The vulnerability ID is CVE-2020-26890.
What is the severity of CVE-2020-26890?
The severity of CVE-2020-26890 is high, with a severity value of 7.5.
What software is affected by CVE-2020-26890?
Matrix Synapse versions up to 1.20.0, Fedora versions 32 and 33 are affected by CVE-2020-26890.
What is the impact of CVE-2020-26890?
CVE-2020-26890 allows remote attackers to execute a denial of service attack against the federation and common Matrix clients.
How can CVE-2020-26890 be fixed?
To fix CVE-2020-26890, it is recommended to upgrade to Matrix Synapse version 1.20.0 or later.
- collector/nvd-index
- vendor/matrix
- canonical/matrix synapse
- vendor/fedoraproject
- canonical/fedoraproject fedora
- version/fedoraproject fedora/32
- version/fedoraproject fedora/33