Vulnerability Details CVE-2025-61771
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` stores non-file form fields (parts without a `filename`) entirely in memory as Ruby `String` objects. A single large text field in a multipart/form-data request (hundreds of megabytes or more) can consume equivalent process memory, potentially leading to out-of-memory (OOM) conditions and denial of service (DoS). Attackers can send large non-file fields to trigger excessive memory usage. Impact scales with request size and concurrency, potentially leading to worker crashes or severe garbage-collection overhead. All Rack applications processing multipart form submissions are affected. Versions 2.2.19, 3.1.17, and 3.2.2 enforce a reasonable size cap for non-file fields (e.g., 2 MiB). Workarounds include restricting maximum request body size at the web-server or proxy layer (e.g., Nginx `client_max_body_size`) and validating and rejecting unusually large form fields at the application level.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 12.2%
CVSS Severity
CVSS v3 Score 7.5
References
Products affected by CVE-2025-61771
-
cpe:2.3:a:rack:rack:0.1
-
cpe:2.3:a:rack:rack:0.2
-
cpe:2.3:a:rack:rack:0.3
-
cpe:2.3:a:rack:rack:0.4
-
cpe:2.3:a:rack:rack:0.9
-
cpe:2.3:a:rack:rack:0.9.1
-
cpe:2.3:a:rack:rack:1.0
-
cpe:2.3:a:rack:rack:1.0.1
-
cpe:2.3:a:rack:rack:1.1
-
cpe:2.3:a:rack:rack:1.1.2
-
cpe:2.3:a:rack:rack:1.1.3
-
cpe:2.3:a:rack:rack:1.1.4
-
cpe:2.3:a:rack:rack:1.1.5
-
cpe:2.3:a:rack:rack:1.1.6
-
cpe:2.3:a:rack:rack:1.2
-
cpe:2.3:a:rack:rack:1.2.1
-
cpe:2.3:a:rack:rack:1.2.2
-
cpe:2.3:a:rack:rack:1.2.3
-
cpe:2.3:a:rack:rack:1.2.4
-
cpe:2.3:a:rack:rack:1.2.5
-
cpe:2.3:a:rack:rack:1.2.6
-
cpe:2.3:a:rack:rack:1.2.7
-
cpe:2.3:a:rack:rack:1.2.8
-
cpe:2.3:a:rack:rack:1.3.0
-
cpe:2.3:a:rack:rack:1.3.1
-
cpe:2.3:a:rack:rack:1.3.10
-
cpe:2.3:a:rack:rack:1.3.2
-
cpe:2.3:a:rack:rack:1.3.3
-
cpe:2.3:a:rack:rack:1.3.4
-
cpe:2.3:a:rack:rack:1.3.5
-
cpe:2.3:a:rack:rack:1.3.6
-
cpe:2.3:a:rack:rack:1.3.7
-
cpe:2.3:a:rack:rack:1.3.8
-
cpe:2.3:a:rack:rack:1.3.9
-
cpe:2.3:a:rack:rack:1.4.0
-
cpe:2.3:a:rack:rack:1.4.1
-
cpe:2.3:a:rack:rack:1.4.2
-
cpe:2.3:a:rack:rack:1.4.3
-
cpe:2.3:a:rack:rack:1.4.4
-
cpe:2.3:a:rack:rack:1.4.5
-
cpe:2.3:a:rack:rack:1.4.6
-
cpe:2.3:a:rack:rack:1.4.7
-
cpe:2.3:a:rack:rack:1.5.0
-
cpe:2.3:a:rack:rack:1.5.1
-
cpe:2.3:a:rack:rack:1.5.2
-
cpe:2.3:a:rack:rack:1.5.3
-
cpe:2.3:a:rack:rack:1.5.4
-
cpe:2.3:a:rack:rack:1.5.5
-
cpe:2.3:a:rack:rack:1.6.0
-
cpe:2.3:a:rack:rack:1.6.1
-
cpe:2.3:a:rack:rack:1.6.10
-
cpe:2.3:a:rack:rack:1.6.11
-
cpe:2.3:a:rack:rack:1.6.12
-
cpe:2.3:a:rack:rack:1.6.13
-
cpe:2.3:a:rack:rack:1.6.2
-
cpe:2.3:a:rack:rack:1.6.3
-
cpe:2.3:a:rack:rack:1.6.4
-
cpe:2.3:a:rack:rack:1.6.5
-
cpe:2.3:a:rack:rack:1.6.6
-
cpe:2.3:a:rack:rack:1.6.7
-
cpe:2.3:a:rack:rack:1.6.8
-
cpe:2.3:a:rack:rack:1.6.9
-
cpe:2.3:a:rack:rack:2.0.0
-
cpe:2.3:a:rack:rack:2.0.1
-
cpe:2.3:a:rack:rack:2.0.2
-
cpe:2.3:a:rack:rack:2.0.3
-
cpe:2.3:a:rack:rack:2.0.4
-
cpe:2.3:a:rack:rack:2.0.5
-
cpe:2.3:a:rack:rack:2.0.6
-
cpe:2.3:a:rack:rack:2.0.7
-
cpe:2.3:a:rack:rack:2.0.8
-
cpe:2.3:a:rack:rack:2.0.9
-
cpe:2.3:a:rack:rack:2.0.9.2
-
cpe:2.3:a:rack:rack:2.0.9.3
-
cpe:2.3:a:rack:rack:2.1.0
-
cpe:2.3:a:rack:rack:2.1.1
-
cpe:2.3:a:rack:rack:2.1.2
-
cpe:2.3:a:rack:rack:2.1.3
-
cpe:2.3:a:rack:rack:2.1.4
-
cpe:2.3:a:rack:rack:2.1.4.2
-
cpe:2.3:a:rack:rack:2.1.4.3
-
cpe:2.3:a:rack:rack:2.2.0
-
cpe:2.3:a:rack:rack:2.2.1
-
cpe:2.3:a:rack:rack:2.2.10
-
cpe:2.3:a:rack:rack:2.2.11
-
cpe:2.3:a:rack:rack:2.2.12
-
cpe:2.3:a:rack:rack:2.2.13
-
cpe:2.3:a:rack:rack:2.2.14
-
cpe:2.3:a:rack:rack:2.2.15
-
cpe:2.3:a:rack:rack:2.2.16
-
cpe:2.3:a:rack:rack:2.2.17
-
cpe:2.3:a:rack:rack:2.2.18
-
cpe:2.3:a:rack:rack:2.2.2
-
cpe:2.3:a:rack:rack:2.2.3
-
cpe:2.3:a:rack:rack:2.2.4
-
cpe:2.3:a:rack:rack:2.2.4.1
-
cpe:2.3:a:rack:rack:2.2.5
-
cpe:2.3:a:rack:rack:2.2.6
-
cpe:2.3:a:rack:rack:2.2.6.1
-
cpe:2.3:a:rack:rack:2.2.6.2
-
cpe:2.3:a:rack:rack:2.2.6.3
-
cpe:2.3:a:rack:rack:2.2.6.4
-
cpe:2.3:a:rack:rack:2.2.7
-
cpe:2.3:a:rack:rack:2.2.8
-
cpe:2.3:a:rack:rack:2.2.8.1
-
cpe:2.3:a:rack:rack:2.2.9
-
cpe:2.3:a:rack:rack:3.1.0
-
cpe:2.3:a:rack:rack:3.1.1
-
cpe:2.3:a:rack:rack:3.1.10
-
cpe:2.3:a:rack:rack:3.1.11
-
cpe:2.3:a:rack:rack:3.1.12
-
cpe:2.3:a:rack:rack:3.1.13
-
cpe:2.3:a:rack:rack:3.1.14
-
cpe:2.3:a:rack:rack:3.1.15
-
cpe:2.3:a:rack:rack:3.1.16
-
cpe:2.3:a:rack:rack:3.1.2
-
cpe:2.3:a:rack:rack:3.1.3
-
cpe:2.3:a:rack:rack:3.1.4
-
cpe:2.3:a:rack:rack:3.1.5
-
cpe:2.3:a:rack:rack:3.1.6
-
cpe:2.3:a:rack:rack:3.1.7
-
cpe:2.3:a:rack:rack:3.1.8
-
cpe:2.3:a:rack:rack:3.1.9
-
cpe:2.3:a:rack:rack:3.2.0
-
cpe:2.3:a:rack:rack:3.2.1