How severe is CVE-2024-52815?

No CVSS score has been assigned to CVE-2024-52815 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2024-52815?

CVE-2024-52815 affects the following packages: matrix-synapse (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2024-52815?

Update matrix-synapse to 1.120.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-52815 is resolved across your whole dependency graph.

How do I detect CVE-2024-52815 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-2024-52815 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2024-52815 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-52815 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-2024-52815?

CVE-2024-52815 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 47th 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-2024-52815?

CVE-2024-52815 is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-52815 published, and has it been updated?

CVE-2024-52815 was published on December 3, 2024 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

CVE-2024-52815 — matrix-synapse

CVE-2024-52815 is a Improper Input Validation vulnerability in matrix-synapse. A fix is available for matrix-synapse — see the affected versions and patch details below.

Synapse allows a a malformed invite to break the invitee's `/sync`

Also known asGHSA-f3r3-h2mq-hx2hPYSEC-2026-1611

Published

Dec 3, 2024

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
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-2024-52815.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs47th percentile — riskier than 47% of all scored CVEsHighest risk

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

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

Synapse versions before 1.120.1 fail to properly validate invites received over federation. This vulnerability allows a malicious server to send a specially crafted invite that disrupts the invited user's /sync functionality.

Patches

Synapse 1.120.1 rejects such invalid invites received over federation and restores the ability to sync for affected users.

Workarounds

Server administrators can disable federation from untrusted servers.

For more information

If you have any questions or comments about this advisory, please email us at security at element.io.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`matrix-synapse`	all versions	1.120.1`pip install --upgrade 'matrix-synapse==1.120.1'`

Affected Products

1 product · 1 configurations

Application

synapsematrix

< 1.120.1

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 1.120.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-52815 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact Synapse versions before 1.120.1 fail to properly validate invites received over federation. This vulnerability allows a malicious server to send a specially crafted invite that disrupts the invited user's `/sync` functionality. ### Patches Synapse 1.120.1 rejects such invalid invites received over federation and restores the ability to sync for affected users. ### Workarounds Server administrators can disable federation from untrusted servers. ### For more information If you have any questions or comments about this advisory, please email us at [security at element.io](mailto

O3 Security · Impact-Aware SCA

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CVE-2024-52815 — matrix-synapse

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

Real-World Exposure

Description

Impact

Patches

Workarounds

For more information

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2024-52815 in your dependencies?