CVE-2021-21393
Scores
EPSS
Percentile: 0.0%
CVSS
CVSS Score: 6.5/10
All CVSS Scores
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Vector Breakdown
CVSS (Common Vulnerability Scoring System) vector provides detailed metrics about vulnerability characteristics
CVSS
Attack Vector
Network (N)
Describes how the vulnerability is exploited
Attack Complexity
Low (L)
Describes the conditions beyond the attacker's control
Privileges Required
Low (L)
Describes the level of privileges an attacker must possess
User Interaction
None (N)
Captures the requirement for a human user participation
Scope
Unchanged (U)
Determines if a successful attack impacts components beyond the vulnerable component
Confidentiality Impact
None (N)
Measures the impact to the confidentiality of information
Integrity Impact
None (N)
Measures the impact to integrity of a successfully exploited vulnerability
Availability Impact
High (H)
Measures the impact to the availability of the impacted component
Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P
Vector Breakdown
CVSS (Common Vulnerability Scoring System) vector provides detailed metrics about vulnerability characteristics
CVSS
Attack Vector
Network (N)
Describes how the vulnerability is exploited
Attack Complexity
Medium
Describes the conditions beyond the attacker's control
Authentication
None (N)
Describes the level of privileges an attacker must possess
Confidentiality Impact
None (N)
Measures the impact to the confidentiality of information
Integrity Impact
None (N)
Measures the impact to integrity of a successfully exploited vulnerability
Availability Impact
Partial
Measures the impact to the availability of the impacted component
Description
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.
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Sources
CWEs
Vulnerable Software (12)
Type: Configuration
Product: matrix-synapse
Operating System: debian
{ "fixed": "1.28.0-1"}
Source: debian
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu bionic 18.04
{ "unaffected": true}
Source: ubuntu
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu focal 20.04
{ "unfixed": true}
Source: ubuntu
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu groovy 20.10
{ "unfixed": true}
Source: ubuntu
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu hirsute 21.04
{ "unfixed": true}
Source: ubuntu
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu impish 21.10
{ "unfixed": true}
Source: ubuntu
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu jammy 22.04
{ "unfixed": true}
Source: ubuntu
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu kinetic 22.10
{ "unfixed": true}
Source: ubuntu
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu lunar 23.04
{ "unaffected": true}
Source: ubuntu
Type: Configuration
Product: matrix-synapse
Operating System: ubuntu trusty 14.04
{ "unfixed": true}
Source: ubuntu
Type: Configuration
Vendor: fedoraproject
Product: fedora
Operating System: * * *
{ "cpe_match": [ { "cpe23uri": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*", "vulnerable": true } ], "operator": "OR"}
Source: nvd
Type: Configuration
Vendor: matrix
Product: synapse
Operating System: * * *
{ "cpe_match": [ { "cpe23uri": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.28.0", "versionStartExcluding": "0.24.0", "vulnerable": true } ...
{ "cpe_match": [ { "cpe23uri": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.28.0", "versionStartExcluding": "0.24.0", "vulnerable": true } ], "operator": "OR"}
Source: nvd