CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:S/C:N/I:N/A:P
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
AI Score
Confidence
High
EPSS
Percentile
49.1%
Synapse is an open source home server implementation for the Matrix chat network. In versions prior to 1.61.1 URL previews of some web pages can exhaust the available stack space for the Synapse process due to unbounded recursion. This is sometimes recoverable and leads to an error for the request causing the problem, but in other cases the Synapse process may crash altogether. It is possible to exploit this maliciously, either by malicious users on the homeserver, or by remote users sending URLs that a local user’s client may automatically request a URL preview for. Remote users are not able to exploit this directly, because the URL preview endpoint is authenticated. Deployments with url_preview_enabled: false
set in configuration are not affected. Deployments with url_preview_enabled: true
set in configuration are affected. Deployments with no configuration value set for url_preview_enabled
are not affected, because the default is false
. Administrators of homeservers with URL previews enabled are advised to upgrade to v1.61.1 or higher. Users unable to upgrade should set url_preview_enabled
to false.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
Alpine | edge-community | noarch | synapse | < 1.61.1-r0 | UNKNOWN |
Alpine | 3.16-community | noarch | synapse | < 1.61.1-r0 | UNKNOWN |
Alpine | 3.17-community | noarch | synapse | < 1.61.1-r0 | UNKNOWN |
Alpine | 3.18-community | noarch | synapse | < 1.61.1-r0 | UNKNOWN |
Alpine | 3.19-community | noarch | synapse | < 1.61.1-r0 | UNKNOWN |
Alpine | 3.20-community | noarch | synapse | < 1.61.1-r0 | UNKNOWN |
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:S/C:N/I:N/A:P
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
AI Score
Confidence
High
EPSS
Percentile
49.1%