CVE-2023-32683Network attack vector

SSRF via unchecked discovered preview URLs

Published Jun 6, 2023 · Updated Feb 13, 2025

SSRF in Matrix.org Synapse before 1.85.0 allows remote authenticated users to bypass configured URL preview deny rules. The URL previewer checks the submitted page URL but omits the same deny-list check for discovered oEmbed and image URLs. A Matrix account, another user's preview action, URL previews, and a configured URL deny list are required; reachable addresses and returned content remain restricted.

CVSS severity3.5
Low
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Matrix.org Synapse before 1.85.0 allows remote authenticated users to bypass configured URL preview deny rules. The URL previewer checks the submitted page URL but omits the same deny-list check for discovered oEmbed and image URLs. A Matrix account, another user's preview action, URL previews, and a configured URL deny list are required; reachable addresses and returned content remain restricted.

The record

CVE
CVE-2023-32683
Published
Jun 6, 2023
Updated
Feb 13, 2025
Vendor
Matrix.org
Product
Synapse
Classifications
CWE-863, CWE-918, T1090
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 6, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.85.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Matrix.org · Synapseversion=< 1.85.0

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
3.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
CWE-918Server-Side Request Forgery (SSRF)
T1090Proxy

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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