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.
CVE-2025-61771
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 71% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 41.4%
- KEV
- Not listed
Published
October 7, 2025
Last Modified
June 17, 2026
References (4)
- security-advisories@githubhttps://github.com/rack/rack/commit/589127f4ac8b5cf11cf88fb0cd116ffed4d2181e
- security-advisories@githubhttps://github.com/rack/rack/commit/d869fed663b113b95a74ad53e1b5cae6ab31f29e
- security-advisories@githubhttps://github.com/rack/rack/commit/e08f78c656c9394d6737c022bde087e0f33336fd
- security-advisories@githubhttps://github.com/rack/rack/security/advisories/GHSA-w9pc-fmgc-vxvw
Vendor Advisories for CVE-2025-61771(10)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2025:21696Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:21036Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:20962Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:19948Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:19800Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:19734Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:19719Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:19647Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- +2 more
Patch Availability(11)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | ruby-rack (3.1.16-0.1ubuntu0.1) @ questing | 2026-05-29 | ubuntu |
| redhat | pcs-0:0.9.169-3.el7_9.5 | 2025-11-18 | redhat |
| redhat | pcs-0:0.12.1-1.el10_1.1 | 2025-11-11 | redhat |
| redhat | pcs-0:0.11.10-1.el9_7.1 | 2025-11-11 | redhat |
| redhat | pcs-0:0.10.8-1.el8_4.8 | 2025-11-10 | redhat |
| redhat | pcs-0:0.11.1-10.el9_0.9 | 2025-11-05 | redhat |
| redhat | pcs-0:0.10.12-6.el8_6.10 | 2025-11-04 | redhat |
| redhat | pcs-0:0.10.18-2.el8_10.7 | 2025-11-04 | redhat |
| redhat | pcs-0:0.10.15-4.el8_8.9 | 2025-11-04 | redhat |
| redhat | pcs-0:0.12.0-3.el10_0.3 | 2025-11-03 | redhat |
| redhat | pcs-0:0.11.9-2.el9_6.2 | 2025-11-03 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
RubyGems(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| rack | 3.2.0, 3.2.1 | 3.2.2 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(1)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 9× in last 7d / 44× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:24 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:30 UTCEPSS rescore
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- 2026-07-19 02:28 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
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- 2026-07-16 17:02 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 01:59 UTCEPSS rescore
- 2026-07-15 01:59 UTCEPSS rescore
- 2026-07-13 22:29 UTCEPSS rescore
- 2026-07-13 06:12 UTCEPSS rescore
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:09 UTCEPSS rescore
- 2026-07-08 15:15 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 12:41 UTCOSV refresh
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
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- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
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- 2026-07-01 15:06 UTCEPSS rescore
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-28 04:55 UTCEPSS rescore
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-24 14:04 UTCEPSS rescore
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- 2026-06-23 21:32 UTCEPSS rescore
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- 2026-06-22 14:25 UTCEPSS rescore
- 2026-06-21 14:56 UTCEPSS rescore
- 2026-06-21 14:56 UTCEPSS rescore
- 2026-06-21 01:59 UTCEPSS rescore
- 2026-06-21 01:59 UTCEPSS rescore
- 2026-06-19 19:25 UTCEPSS rescore
- 2026-06-19 19:25 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-18 00:43 UTCOSV refresh
- 2026-06-17 17:52 UTCEPSS rescore
- 2026-06-16 17:52 UTCEPSS rescore
- 2026-06-15 17:48 UTCEPSS rescore
- 2026-06-15 17:48 UTCEPSS rescore
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
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- 2026-06-11 14:00 UTCEPSS rescore
- 2026-06-10 22:18 UTCEPSS rescore
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- 2026-06-10 13:22 UTCEPSS rescore
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-08 14:16 UTCEPSS rescore
- 2026-06-07 15:24 UTCEPSS rescore
- 2026-06-07 15:24 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-05 22:46 UTCEPSS rescore
- 2026-06-05 22:46 UTCEPSS rescore
- 2026-06-05 06:10 UTCEPSS rescore
- 2026-06-05 06:10 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-02 20:13 UTCEPSS rescore
- 2026-06-02 20:12 UTCEPSS rescore
- 2026-06-01 13:51 UTCEPSS rescore
- 2026-06-01 13:51 UTCEPSS rescore
- 2026-05-31 22:30 UTCEPSS rescore
- 2026-05-31 22:30 UTCEPSS rescore
- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-29 21:21 UTCEG score recompute
- 2026-05-29 21:21 UTCVendor advisory
- 2026-05-29 15:57 UTCOSV refresh
- 2026-05-29 13:44 UTCEPSS rescore
Related CVEs(same vendor + same CWE)
Same vendor
10 shownredhat
Same CWE
10 shownCWE-400
Frequently asked(5)
What is CVE-2025-61771?
When was CVE-2025-61771 disclosed?
Is CVE-2025-61771 actively exploited?
What is the CVSS score of CVE-2025-61771?
How do I remediate CVE-2025-61771?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2025-61771
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