4.3 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:N/I:N/A:P
6.5 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
0.002 Low
EPSS
Percentile
57.3%
Synapse is a Matrix reference homeserver written in python (pypi package
matrix-synapse). Matrix is an ecosystem for open federated Instant
Messaging and VoIP. In Synapse before version 1.28.0 Synapse is missing
input validation of some parameters on the endpoints used to confirm
third-party identifiers could cause excessive use of disk space and memory
leading to resource exhaustion. Note that the groups feature is not part of
the Matrix specification and the chosen maximum lengths are arbitrary. Not
all clients might abide by them. Refer to referenced GitHub security
advisory for additional details including workarounds.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 20.04 | noarch | matrix-synapse | < any | UNKNOWN |
ubuntu | 22.04 | noarch | matrix-synapse | < any | UNKNOWN |
github.com/matrix-org/synapse/pull/9321
github.com/matrix-org/synapse/pull/9393
github.com/matrix-org/synapse/security/advisories/GHSA-jrh7-mhhx-6h88
launchpad.net/bugs/cve/CVE-2021-21393
nvd.nist.gov/vuln/detail/CVE-2021-21393
pypi.org/project/matrix-synapse/
security-tracker.debian.org/tracker/CVE-2021-21393
www.cve.org/CVERecord?id=CVE-2021-21393
4.3 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:N/I:N/A:P
6.5 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
0.002 Low
EPSS
Percentile
57.3%