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Full vulnerability report · 2025
CVE-2025-61770High confidence

Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion)

rack · rack

Official source article: GitHub GHSA-P543-XPFM-54CP ↗. Check the applicable product and release in the original source.

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.93% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs rack rack and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

5 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourceruby-rackVendor fix publishedDebian records a fixed source-package version for this release.3.1.18-1~deb13u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourceruby-rackVendor fix publishedDebian records a fixed source-package version for this release.2.2.20-0+deb12u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourceruby-rackVendor fix publishedDebian records a fixed source-package version for this release.3.1.18-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourceruby-rackVendor fix publishedDebian records a fixed source-package version for this release.3.1.18-1Debian Security Tracker ↗Source updated 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archiveruby-rackVendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.2.2.7-1ubuntu0.5Canonical Ubuntu Security ↗Source updated 5 Oct 2026
Open-source package ranges6 source-attributed ranges

These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.

Ecosystem and packageAffected rangeFirst fixed versionEvidence
RubyGemsrackECOSYSTEM: introduced 0; fixed 2.2.192.2.19OSV record ↗aggregator derived · 10 Sep 2026
RubyGemsrackECOSYSTEM: introduced 3.1; fixed 3.1.173.1.17OSV record ↗aggregator derived · 10 Sep 2026
RubyGemsrackECOSYSTEM: introduced 3.2; fixed 3.2.23.2.2OSV record ↗aggregator derived · 10 Sep 2026
rubygemsrack< 2.2.192.2.19GitHub advisory ↗upstream repository advisory · 13 Oct 2025
rubygemsrack>= 3.1, < 3.1.173.1.17GitHub advisory ↗upstream repository advisory · 13 Oct 2025
rubygemsrack>= 3.2, < 3.2.23.2.2GitHub advisory ↗upstream repository advisory · 13 Oct 2025
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2025-61770 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityrack: Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion)
8 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • 3scale-amp2/zync-rhel7 as a component of Red Hat 3scale API Management Platform 2
  • 3scale-amp2/zync-rhel8 as a component of Red Hat 3scale API Management Platform 2
  • 3scale-amp2/zync-rhel9 as a component of Red Hat 3scale API Management Platform 2
  • 3scale-amp21/zync as a component of Red Hat 3scale API Management Platform 2
  • 3scale-amp22/zync as a component of Red Hat 3scale API Management Platform 2
  • 3scale-amp24/zync as a component of Red Hat 3scale API Management Platform 2
  • 3scale-amp25/zync as a component of Red Hat 3scale API Management Platform 2
  • 3scale-amp26/zync as a component of Red Hat 3scale API Management Platform 2
Summary
A flaw was found in Rack where the Rack::Multipart::Parser buffers the multipart preamble memory without size limits. A remote attacker can send a crafted multipart/form-data request with a very large preamble before its first boundary, causing excessive memory consumption and denial of service crash due to out-of-memory issue.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2025-32057

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

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.

What

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.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

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.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Uncontrolled Resource Consumption → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-400 ↗

CWE-400: Uncontrolled Resource Consumption. The product does not properly control the allocation and maintenance of a limited resource.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-400
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2025-2482Red Hat Enterprise Linux: Mehrere Schwachstellen ermöglichen Denial of Service

Ein Angreifer kann mehrere Schwachstellen in Red Hat Enterprise Linux ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20251008Security Bulletin 08 Oct 2025

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 08 Oct 2025, published on 8 October 2025. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0326Multiples vulnérabilités dans les produits VMware

d?id=CVE-2025-61724 Référence CVE CVE-2025-61725 https://www.cve.org/CVERecord?id=CVE-2025-61725 Référence CVE CVE-2025-61726 https://www.cve.org/CVERecord?id=CVE-2025-61726 Référence CVE CVE-2025-61727 https://www.cve.org/CVERecord?id=CVE-2025-61727 Référence CVE CVE-2025-61728 https://www.cve.org/CVERecord?id=CVE-2025-61728 Référence CVE CVE-2025-61729 https://www.cve.org/CVERecord?id=CVE-2025-61729 Référence CVE CVE-2025-61730 https://www.cve.org/CVERecord?id=CVE-2025-61730 Référence CVE CVE-2025-61731 https://www.cve.org/CVERecord?id=CVE-2025-61731 Référence CVE CVE-2025-61732 https://www.cve.org/CVERecord?id=CVE-2025-61732 Référence CVE CVE-2025-61770 https://www.cve.org/CVERecord?id=CVE-2025-61770 Référence CVE CVE-2025-61771 https://www.cve.org/CVERecord?id=CVE-2025-61771 Référence CVE CVE-2025-61772 https://www.cve.org/CVERecord?id=CVE-2025-61772 Référence CVE CVE-2025-61780 https://www.cve.org/CVERecord?id=CVE-2025-61780 Référence CVE CVE-2025-61795 https://www.cve.org/CVERecord?id=CVE-2025-61795 Référence CVE CVE-2025-61919 https://www.cve.org/CVERecord?id=CVE-2025-61919 Référence CVE CVE-2025-61984 https://www.cve.org/CVERecord?id=CVE-2025-61984 Référence CVE CVE-2025-61985 https://www.cve.org/CVERecord?id=CVE-2025-61985 Référence CVE CVE-2025-62525 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-1129Multiples vulnérabilités dans les produits VMware

rd?id=CVE-2025-5889 Référence CVE CVE-2025-59419 https://www.cve.org/CVERecord?id=CVE-2025-59419 Référence CVE CVE-2025-59830 https://www.cve.org/CVERecord?id=CVE-2025-59830 Référence CVE CVE-2025-61723 https://www.cve.org/CVERecord?id=CVE-2025-61723 Référence CVE CVE-2025-61724 https://www.cve.org/CVERecord?id=CVE-2025-61724 Référence CVE CVE-2025-61725 https://www.cve.org/CVERecord?id=CVE-2025-61725 Référence CVE CVE-2025-61727 https://www.cve.org/CVERecord?id=CVE-2025-61727 Référence CVE CVE-2025-61729 https://www.cve.org/CVERecord?id=CVE-2025-61729 Référence CVE CVE-2025-61748 https://www.cve.org/CVERecord?id=CVE-2025-61748 Référence CVE CVE-2025-61770 https://www.cve.org/CVERecord?id=CVE-2025-61770 Référence CVE CVE-2025-61771 https://www.cve.org/CVERecord?id=CVE-2025-61771 Référence CVE CVE-2025-61772 https://www.cve.org/CVERecord?id=CVE-2025-61772 Référence CVE CVE-2025-61780 https://www.cve.org/CVERecord?id=CVE-2025-61780 Référence CVE CVE-2025-61795 https://www.cve.org/CVERecord?id=CVE-2025-61795 Référence CVE CVE-2025-61919 https://www.cve.org/CVERecord?id=CVE-2025-61919 Référence CVE CVE-2025-64329 https://www.cve.org/CVERecord?id=CVE-2025-64329 Référence CVE CVE-2025-64756 https://www.cve.org/CVERecord?id=CVE-2025-64756 Référence CVE CVE-2025-66030 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0969Multiples vulnérabilités dans les produits VMware

ve.org/CVERecord?id=CVE-2025-5994 Référence CVE CVE-2025-6020 https://www.cve.org/CVERecord?id=CVE-2025-6020 Référence CVE CVE-2025-6021 https://www.cve.org/CVERecord?id=CVE-2025-6021 Référence CVE CVE-2025-6051 https://www.cve.org/CVERecord?id=CVE-2025-6051 Référence CVE CVE-2025-6052 https://www.cve.org/CVERecord?id=CVE-2025-6052 Référence CVE CVE-2025-6069 https://www.cve.org/CVERecord?id=CVE-2025-6069 Référence CVE CVE-2025-6141 https://www.cve.org/CVERecord?id=CVE-2025-6141 Référence CVE CVE-2025-6170 https://www.cve.org/CVERecord?id=CVE-2025-6170 Référence CVE CVE-2025-61748 https://www.cve.org/CVERecord?id=CVE-2025-61748 Référence CVE CVE-2025-61770 https://www.cve.org/CVERecord?id=CVE-2025-61770 Référence CVE CVE-2025-61771 https://www.cve.org/CVERecord?id=CVE-2025-61771 Référence CVE CVE-2025-61772 https://www.cve.org/CVERecord?id=CVE-2025-61772 Référence CVE CVE-2025-61780 https://www.cve.org/CVERecord?id=CVE-2025-61780 Référence CVE CVE-2025-61795 https://www.cve.org/CVERecord?id=CVE-2025-61795 Référence CVE CVE-2025-61919 https://www.cve.org/CVERecord?id=CVE-2025-61919 Référence CVE CVE-2025-61921 https://www.cve.org/CVERecord?id=CVE-2025-61921 Référence CVE CVE-2025-61984 https://www.cve.org/CVERecord?id=CVE-2025-61984 Référence CVE CVE-2025-61985 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0967Multiples vulnérabilités dans les produits VMware

ord?id=CVE-2025-58057 Référence CVE CVE-2025-58446 https://www.cve.org/CVERecord?id=CVE-2025-58446 Référence CVE CVE-2025-58754 https://www.cve.org/CVERecord?id=CVE-2025-58754 Référence CVE CVE-2025-58767 https://www.cve.org/CVERecord?id=CVE-2025-58767 Référence CVE CVE-2025-59425 https://www.cve.org/CVERecord?id=CVE-2025-59425 Référence CVE CVE-2025-59830 https://www.cve.org/CVERecord?id=CVE-2025-59830 Référence CVE CVE-2025-6069 https://www.cve.org/CVERecord?id=CVE-2025-6069 Référence CVE CVE-2025-61620 https://www.cve.org/CVERecord?id=CVE-2025-61620 Référence CVE CVE-2025-61748 https://www.cve.org/CVERecord?id=CVE-2025-61748 Référence CVE CVE-2025-61770 https://www.cve.org/CVERecord?id=CVE-2025-61770 Référence CVE CVE-2025-61771 https://www.cve.org/CVERecord?id=CVE-2025-61771 Référence CVE CVE-2025-61772 https://www.cve.org/CVERecord?id=CVE-2025-61772 Référence CVE CVE-2025-61780 https://www.cve.org/CVERecord?id=CVE-2025-61780 Référence CVE CVE-2025-61795 https://www.cve.org/CVERecord?id=CVE-2025-61795 Référence CVE CVE-2025-61919 https://www.cve.org/CVERecord?id=CVE-2025-61919 Référence CVE CVE-2025-61921 https://www.cve.org/CVERecord?id=CVE-2025-61921 Référence CVE CVE-2025-6242 https://www.cve.org/CVERecord?id=CVE-2025-6242 Référence CVE CVE-2025-8194 https://www.cve.org/CVERecord?id=CVE

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2025-016072Ruby 用 Rack におけるリソースの枯渇に関する脆弱性

Ruby 用 Rack には、リソースの枯渇に関する脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Action
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Workaround
A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
04

Evidence and provenance

Published 7 Oct 2025 · Last source change 7 Oct 2025, 15:43 UTC · CWE-400 · Uncontrolled Resource Consumption

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2025-32057
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    < 2.2.19; >= 3.1, < 3.1.17; >= 3.2, < 3.2.2 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    < 2.2.19; >= 3.1, < 3.1.17; >= 3.2, < 3.2.2 · Fixed: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
    Red Hat Product Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2025-32057↗Red Hat Product Security security advisory↗CVE authority or vendor reference · GitHub GHSA-P543-XPFM-54CP↗Patch or update reference↗Patch or update reference↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2025-61770 · cve.blacktree.nl