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CVE-2023-32683

URL deny list bypass via oEmbed and image URLs when generating previews in Synapse

Published: Jun 6, 2023Updated: Nov 21, 2024 Sources: CVE List NVD GHSACWE-863
NVD MITRE
3.5CVSSLOW
EPSS Score
0.6%
Top 55.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

Synapse is a Matrix protocol homeserver written in Python with the Twisted framework. A discovered oEmbed or image URL can bypass the `url_preview_url_blacklist` setting potentially allowing server side request forgery or bypassing network policies. Impact is limited to IP addresses allowed by the `url_preview_ip_range_blacklist` setting (by default this only allows public IPs) and by the limited information returned to the client: 1. For discovered oEmbed URLs, any non-JSON response or a JSON response which includes non-oEmbed information is discarded. 2. For discovered image URLs, any non-image response is discarded. Systems which have URL preview disabled (via the `url_preview_enabled` setting) or have not configured a `url_preview_url_blacklist` are not affected. This issue has been addressed in version 1.85.0. Users are advised to upgrade. User unable to upgrade may also disable URL previews.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:RS:UC:NI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-863CWE-918

Affected Products

synapsematrix-org
On-premWeb App
Communications / messaging-chat
matrix-synapsePyPIOSS Libraries
synapsematrix
On-premWeb App
Communications / messaging-chat
matrix-orgoss-projectDECommunicationsaka synapse, matrix-js-sdk, matrix appservice irc
pypipackage-ecosystemOSS Libraries
matrixoss-projectGBCommunicationsaka synapse, matrix irc bridge, javascript sdk

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available
Workaround Available

MITRE ATT&CK

3 techniques
Command and Control
Initial Access
View detailed technique mapping

References

https://github.com/matrix-org/synapse/security/advisories/GHSA-98px-6486-j7qc
github.com
https://github.com/matrix-org/synapse/pull/15601
github.com
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/X6DH5A5YEB5LRIPP32OUW25FCGZFCZU2/
lists.fedoraproject.org
and 5 more references View all →

Timeline

Published
Jun 6, 2023
Last Updated
Nov 21, 2024

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