CVE-2020-26257 describes a denial-of-service vulnerability in Matrix Synapse homeservers prior to version 1.23.1. A malicious or poorly-implemented homeserver can inject malformed events into a room, preventing future events from being correctly federated to other servers. This affects any server accepting federation requests from untrusted sources, including Fedora Project's Synapse implementation. The vulnerability has a CVSS score of 6.5 (Medium), indicating a network-based attack with low complexity and no user interaction required, leading to high availability impact. While a workaround exists by whitelisting trusted federation domains, the primary fix is upgrading to Synapse 1.23.1 or later. There is no evidence of active exploitation, publicly available exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage regarding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 1.23.1CPE matchmatch criteria | cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* | ||
32CPE matchmatch criteria | cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* | ||
33CPE matchmatch criteria | cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.