CVE-2024-52805High▾ TwilightSynapse allows unsupported content types to lead to memory exhaustion
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
0.7%
0.7% → 0.7%
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.
Limiting request sizes or blocking the multipart/form-data content type before the requests reach Synapse, for example in a reverse proxy, alleviates the issue. Another approach that mitigates the attack is to use a low max_upload_size in Synapse.
If you have any questions or comments about this advisory, please email us at security at element.io.
matrix-synapse < 1.120.1Upgrade to a patched release:
matrix-synapse 1.120.1Connected by shared product, vendor, weakness, or advisory.
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