SB2020112717 - Input validation error in synapse (Alpine package)

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Main Vulnerability Database SB2020112717

SB2020112717 - Input validation error in synapse (Alpine package)

Published: November 27, 2020

Security Bulletin ID SB2020112717
Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 security vulnerability.


1) Input validation error (CVE-ID: CVE-2020-26890)

The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to the application 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.


Remediation

Install update from vendor's website.

References