How severe is CVE-2023-32683?

CVE-2023-32683 has a CVSS score of 3.5/10, rated LOW. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-32683?

CVE-2023-32683 affects the following packages: matrix-synapse (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2023-32683?

Update matrix-synapse to 1.85.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-32683 is resolved across your whole dependency graph.

How do I detect CVE-2023-32683 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for matrix-synapse, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-32683 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2023-32683 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-32683 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-32683?

CVE-2023-32683 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 49th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-32683?

CVE-2023-32683 is classified as CWE-863 (CWE-863), Server-Side Request Forgery (SSRF) (CWE-918). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2023-32683 published, and has it been updated?

CVE-2023-32683 was published on June 6, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

LOW severity

CVE-2023-32683 — matrix-synapse

LOWFix: matrix-org/synapse#15601

CVE-2023-32683 is a low-severity (CVSS 3.5) CWE-863 vulnerability in matrix-synapse. A fix is available for matrix-synapse — see the affected versions and patch details below.

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

Also known asGHSA-98px-6486-j7qcPYSEC-2023-85

Published

Jun 6, 2023

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-32683.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs49th percentile — riskier than 49% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐍matrix-synapse

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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:

For discovered oEmbed URLs, any non-JSON response or a JSON response which includes non-oEmbed information is discarded.
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.

Because of the uncommon configuration required, the limited information a malicious user, and the amount of guesses/time the attack would need; the severity is rated as low.

Patches

The issue is fixed by #15601.

Workarounds

The default configuration of the url_preview_ip_range_blacklist should protect against requests being made to internal infrastructure, URL previews of public URLs is expected.

Alternately URL previews could be disabled using the url_preview_enabled setting.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`matrix-synapse`	all versions	1.85.0`pip install --upgrade 'matrix-synapse==1.85.0'`

Affected Products

1 product · 1 configurations

Application

synapsematrix

< 1.85.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for matrix-synapse, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update matrix-synapse to 1.85.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-32683 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

### Impact 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: * For discovered oEmbed URLs, any non-JSON response or a JSON response which includes non-oEmbed information is discarded. * For discovered image URLs, any non-image response is discarded. Systems which have URL preview disabled (via the