GHSA-w9pc-fmgc-vxvw · Severity: high · Ecosystem: rubygems — Rack: Multipart parser buffers large non‑file fields entirely in memory, enabling DoS (memory exhaustion)
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.
Conclusion & alert: CVE-2025-61771 is rated Low Risk (35.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-10-13 | 0.04% | 0.05% | +0.01% |
| 2 | 2025-10-08 | — | 0.04% | — |
Full EPSS history (2 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
GHSA-w9pc-fmgc-vxvw · Severity: high · Ecosystem: rubygems — Rack: Multipart parser buffers large non‑file fields entirely in memory, enabling DoS (memory exhaustion)
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2025-61771 not yet assigned priority: Debian including 1 source packages (ruby-rack), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2025-61771 |
redhat
|
high | — | https://access.redhat.com/security/cve/CVE-2025-61771 |
suse
|
high | CVE-2025-61771 severity important: SUSE including 10 source package names (pcs-0.10.18-2.el8_10.7, pcs-0.11.10-1.el9_7.1, …), 20 product×package rows across 9 product lines (SUSE Liberty Linux 8, SUSE Liberty Linux 9, … (9 product lines)): Known Not Affected 14, Fixed 6. | https://www.suse.com/security/cve/CVE-2025-61771/ |
ubuntu
|
medium | CVE-2025-61771 medium priority: Ubuntu including 1 source packages (ruby-rack), 9 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): ignored 5, released 3, needs-triage 1. | https://ubuntu.com/security/CVE-2025-61771 |