Vulnerability · Published Nov 24, 2020 · Assigned by mitre
CVE-2020-26890
High 7.5
In plain English
A high-severity security flaw in the synapse package (Alpine). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 3.0% (higher than 87% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | synapse | 1.20.0-r0 | ALPINE-CVE-2020-26890 |
| Alpine:v3.21 | synapse | 1.20.0-r0 | ALPINE-CVE-2020-26890 |
| Alpine:v3.22 | synapse | 1.20.0-r0 | ALPINE-CVE-2020-26890 |
| Alpine:v3.23 | synapse | 1.20.0-r0 | ALPINE-CVE-2020-26890 |
| Alpine:v3.24 | synapse | 1.20.0-r0 | ALPINE-CVE-2020-26890 |
| Debian:14 | matrix-synapse | 1.20.0-1 | DEBIAN-CVE-2020-26890 |
| PyPI | matrix-synapse | 1.20.0 | GHSA-4mp3-385r-v63f |
| PyPI | matrix-synapse | 1.20.0 | PYSEC-2020-237 |
Affected products (as reported)
References
- https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f x_refsource_MISC
- FEDORA-2020-b90dac7fc4 vendor-advisory, x_refsource_FEDORA
- FEDORA-2020-2578d943d2 vendor-advisory, x_refsource_FEDORA