CVE-2020-26890
moderate-risk
Published 2020-11-24
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.
Do I need to act?
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0.95% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10
High
NETWORK
/ LOW complexity
Affected Vendors
References (6)
38
/ 100
moderate-risk
Severity
26/34 · High
Exploitability
3/34 · Minimal
Exposure
9/34 · Low