CVE-2024-52805
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedSynapse is an open-source Matrix homeserver. In Synapse before 1.120.1, multipart/form-data requests can in certain configurations transiently increase memory consumption beyond expected levels while processing the request, which can be used to amplify denial of service attacks. Synapse 1.120.1 resolves the issue by denying requests with unsupported multipart/form-data content type.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceSynapse Matrix homeserver before 1.120.1 contains a denial of service vulnerability where multipart/form-data requests can cause excessive transient memory consumption in certain configurations, amplifying DoS attacks. Version 1.120.1 fixes this by rejecting requests with unsupported multipart/form-data content types.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.120.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Determine installed Synapse versionRun 'python -c "import synapse; print(synapse.__version__)"' or check the package manager version with 'pip show matrix-synapse' or 'apt list --installed | grep synapse' depending on installation methodAffected if Version displayed is below 1.120.1 (e.g., 1.120.0, 1.119.0, etc.)
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Verify Synapse is processing client requestsConfirm the Synapse homeserver is running and accessible - check that port 8008 (or configured client port) is listening and respondingAffected if Server is actively accepting HTTP requests from clients, which includes handling multipart/form-data content in API endpoints
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Identify if multipart/form-data handling is in useReview Synapse access logs for requests containing 'multipart/form-data' in the Content-Type header, or inspect API endpoints that accept file uploadsAffected if Client-server communication involves endpoints that process multipart/form-data requests (such as profile picture uploads, room avatar updates, or file attachments)
You are affected if your installed Synapse version is below 1.120.1 and your server processes multipart/form-data requests from clients.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.120.1
Upgrade Synapse to version 1.120.1 or later, which denies requests with unsupported multipart/form-data content types to prevent memory amplification attacks.
1.120.1 or later
- Ensure you have a backup of your Synapse configuration and database
- Stop the Synapse service
- Upgrade Synapse to version 1.120.1 or later using your installation method (e.g., pip install --upgrade matrix-synapse, docker pull, or system package manager)
- Verify the new version is installed: python -c 'import synapse; print(synapse.__version__)','Restart the Synapse service
- Monitor logs to ensure the server is running correctly and that requests with unsupported multipart/form-data content types are being denied as expected
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2024-52805 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-52805 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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