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.
CVE-2025-61770
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 50% 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)
- EG Risk
- —
- EPSS
- 54.9%
- 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-p543-xpfm-54cp
Vendor Advisories for CVE-2025-61770(12)
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-2025:19736Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:19734Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- RHSA-2025:19733Red Hat Product SecurityHigh
Red Hat Security Advisory: pcs security update
- +4 more
Patch Availability(13)
| 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-0:0.11.10-1.el9_7.1 | 2025-11-11 | redhat |
| redhat | pcs-0:0.12.1-1.el10_1.1 | 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-0:0.11.4-7.el9_2.6 | 2025-11-04 | redhat |
| redhat | pcs-0:0.10.18-2.el8_10.7 | 2025-11-04 | redhat |
| redhat | pcs-0:0.11.7-2.el9_4.5 | 2025-11-04 | redhat |
| redhat | pcs-0:0.10.15-4.el8_8.9 | 2025-11-04 | redhat |
| redhat | pcs-0:0.11.9-2.el9_6.2 | 2025-11-03 | redhat |
| redhat | pcs-0:0.12.0-3.el10_0.3 | 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 / 41× 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
- 2026-07-19 14:30 UTCEPSS rescore
- 2026-07-19 02:28 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 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
- 2026-07-04 06:30 UTCEPSS rescore
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-07-01 15:06 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
- 2026-06-24 14:04 UTCEPSS rescore
- 2026-06-23 21:32 UTCEPSS rescore
- 2026-06-23 21:32 UTCEPSS rescore
- 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
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:11 UTCEPSS rescore
- 2026-06-11 14:00 UTCEPSS rescore
- 2026-06-10 22:18 UTCEPSS rescore
- 2026-06-10 22:18 UTCEPSS rescore
- 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-2025-61770?
When was CVE-2025-61770 disclosed?
Is CVE-2025-61770 actively exploited?
What is the CVSS score of CVE-2025-61770?
How do I remediate CVE-2025-61770?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2025-61770
Is Your Infrastructure Affected by CVE-2025-61770?
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