| CVE-2020-26890 | Date: (C)2020-11-24 (M)2023-12-22 |
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.
CVSS Score and Metrics +CVSS Score and Metrics -| CVSS V3 Severity: | CVSS V2 Severity: |
| CVSS Score : 7.5 | CVSS Score : 5.0 |
| Exploit Score: 3.9 | Exploit Score: 10.0 |
| Impact Score: 3.6 | Impact Score: 2.9 |
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| CVSS V3 Metrics: | CVSS V2 Metrics: |
| Attack Vector: NETWORK | Access Vector: NETWORK |
| Attack Complexity: LOW | Access Complexity: LOW |
| Privileges Required: NONE | Authentication: NONE |
| User Interaction: NONE | Confidentiality: NONE |
| Scope: UNCHANGED | Integrity: NONE |
| Confidentiality: NONE | Availability: PARTIAL |
| Integrity: NONE | |
| Availability: HIGH | |
| | |
