Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion)
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||
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| rack | rack | affected |
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Configuration 1 [-]
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No data.
| Vendor | Product | Versions |
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| Rack | Rack | — |
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4357-1 | ruby-rack security update |
Debian DSA |
DSA-6048-1 | ruby-rack security update |
Github GHSA |
GHSA-p543-xpfm-54cp | Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion) |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.930% probability within 30 days)
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threat_severity
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threat_severity
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| CPEs | cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:* |
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| First Time appeared |
Rack
Rack rack |
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| Vendors & Products |
Rack
Rack rack |
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ssvc
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| Description | 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 limiting total request body size at the proxy or web server level and monitoring memory and set per-process limits to prevent OOM conditions. | |
| Title | Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion) | |
| Weaknesses | CWE-400 | |
| References |
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| Metrics |
cvssV3_1
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