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
EPSS
Percentile
49.1%
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.
url_preview_enabled: false
set in configuration are not affected.url_preview_enabled: true
set in configuration are affected.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.
url_preview_enabled: false
.If you have any questions or comments about this advisory, e-mail us at [email protected].
github.com/matrix-org/synapse
github.com/matrix-org/synapse/commit/fa1308061802ac7b7d20e954ba7372c5ac292333
github.com/matrix-org/synapse/security/advisories/GHSA-22p3-qrh9-cx32
github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2022-224.yaml
lists.fedoraproject.org/archives/list/[email protected]/message/7EARKKJZ2W7WUITFDT4EG4NVATFYJQHF
lists.fedoraproject.org/archives/list/[email protected]/message/QGSDQ4YAITCUACAB7SXQZDJIU3IQ4CJD
nvd.nist.gov/vuln/detail/CVE-2022-31052
spec.matrix.org/v1.2/client-server-api/#get_matrixmediav3preview_url
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
EPSS
Percentile
49.1%