cvedb.io
CVE-2025-61770
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2025-10-07T15:16:02.950 · Last modified 2026-06-17T09:50:52.267

Summary

Rack is a modular Ruby web server interface. In versions prior to 2.2.19, 3.1.17, and 3.2.2, `Rack::Multipart::Parser` buffers the entire multipart preamble (bytes before the first boundary) in memory without any size limit. A client can send a large preamble followed by a valid boundary, causing significant memory use and potential process termination due to out-of-memory (OOM) conditions. Remote attackers can trigger large transient memory spikes by including a long preamble in multipart/form-data requests. The impact scales with allowed request sizes and concurrency, potentially causing worker crashes or severe slowdown due to garbage collection. Versions 2.2.19, 3.1.17, and 3.2.2 enforce a preamble size limit (e.g., 16 KiB) or discard preamble data entirely. Workarounds include limitin

Affected products

rack — rack

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.