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TI-2025-38163 Aliases CVE-2025-61770GHSA-p543-xpfm-54cp

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

Priority MEDIUM 41CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 19 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.

Summary

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 it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0093 60th percentileScored 2026-11-07
Fix Partial rack (rack): 2.2.19, 3.1.17, 3.2.2rack (RubyGems): 2.2.19, 3.1.17, 3.2.2Red Hat: 12 advisoriesRed Hat: 19 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
rackrackbefore 2.2.19; 3.1 to before 3.1.17; 3.2 to before 3.2.22.2.19, 3.1.17, 3.2.2Patch availableCNA
—rack (RubyGems)before 2.2.192.2.19Patch availableGHSA-p543-xpfm-54cp
—rack (RubyGems)3.1 to before 3.1.173.1.17Patch availableGHSA-p543-xpfm-54cp
—rack (RubyGems)3.2 to before 3.2.23.2.2Patch availableGHSA-p543-xpfm-54cp
  • rack Vendorrack Affected before 2.2.19; 3.1 to before 3.1.17; 3.2 to before 3.2.2 Fixed in 2.2.19, 3.1.17, 3.2.2 Patch available CNA
  • rack (RubyGems) Vendor— Affected before 2.2.19 Fixed in 2.2.19 Patch available GHSA-p543-xpfm-54cp
  • rack (RubyGems) Vendor— Affected 3.1 to before 3.1.17 Fixed in 3.1.17 Patch available GHSA-p543-xpfm-54cp
  • rack (RubyGems) Vendor— Affected 3.2 to before 3.2.2 Fixed in 3.2.2 Patch available GHSA-p543-xpfm-54cp

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*before 2.2.19; 3.1.0 to before 3.1.17; 3.2.0 to before 3.2.2Vulnerablerack
  • cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:* Versions before 2.2.19; 3.1.0 to before 3.1.17; 3.2.0 to before 3.2.2 Vulnerable ·rack

Remediation

  • Fix · CNA rack (rack) Fixed in 2.2.19, 3.1.17, 3.2.2
  • Fix · GHSA-p543-xpfm-54cp rack (RubyGems) Fixed in 2.2.19 Advisory →
  • Fix · GHSA-p543-xpfm-54cp rack (RubyGems) Fixed in 3.1.17 Advisory →
  • Fix · GHSA-p543-xpfm-54cp rack (RubyGems) Fixed in 3.2.2 Advisory →

Red Hat 12 advisories

  • RHSA-2025:21696 Released 2025-11-18 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux Server HighAvailability (v. 7 ELS) pcs-0.9.169-3.el7_9.5, pcs-snmp-0.9.169-3.el7_9.5
    • Red Hat Enterprise Linux Server ResilientStorage (v. 7 ELS) pcs-0.9.169-3.el7_9.5, pcs-snmp-0.9.169-3.el7_9.5
  • RHSA-2025:21036 Released 2025-11-11 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability (v. 10) cockpit-ha-cluster-0.12.1-1.el10_1.1, pcs-0.12.1-1.el10_1.1, pcs-snmp-0.12.1-1.el10_1.1
  • RHSA-2025:20962 Released 2025-11-11 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability (v. 9) pcs-0.11.10-1.el9_7.1, pcs-snmp-0.11.10-1.el9_7.1
    • Red Hat Enterprise Linux Resilient Storage (v. 9) pcs-0.11.10-1.el9_7.1, pcs-snmp-0.11.10-1.el9_7.1
Show 9 more Red Hat advisories
  • RHSA-2025:19948 Released 2025-11-10 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability AUS (v.8.4) pcs-0.10.8-1.el8_4.8, pcs-snmp-0.10.8-1.el8_4.8
    • Red Hat Enterprise Linux HighAvailability EUS EXTENSION (v.8.4) pcs-0.10.8-1.el8_4.8, pcs-snmp-0.10.8-1.el8_4.8
  • RHSA-2025:19800 Released 2025-11-05 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability E4S (v.9.0) pcs-0.11.1-10.el9_0.9, pcs-snmp-0.11.1-10.el9_0.9
    • Red Hat Enterprise Linux ResilientStorage E4S (v.9.0) pcs-0.11.1-10.el9_0.9, pcs-snmp-0.11.1-10.el9_0.9
  • RHSA-2025:19736 Released 2025-11-04 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability EUS (v.9.4) pcs-0.11.7-2.el9_4.5, pcs-snmp-0.11.7-2.el9_4.5
    • Red Hat Enterprise Linux Resilient Storage EUS (v.9.4) pcs-0.11.7-2.el9_4.5, pcs-snmp-0.11.7-2.el9_4.5
  • RHSA-2025:19734 Released 2025-11-04 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability E4S (v.8.6) pcs-0.10.12-6.el8_6.10, pcs-snmp-0.10.12-6.el8_6.10
    • Red Hat Enterprise Linux High Availability TUS (v.8.6) pcs-0.10.12-6.el8_6.10, pcs-snmp-0.10.12-6.el8_6.10
  • RHSA-2025:19733 Released 2025-11-04 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability E4S (v.9.2) pcs-0.11.4-7.el9_2.6, pcs-snmp-0.11.4-7.el9_2.6
    • Red Hat Enterprise Linux Resilient Storage E4S (v.9.2) pcs-0.11.4-7.el9_2.6, pcs-snmp-0.11.4-7.el9_2.6
  • RHSA-2025:19719 Released 2025-11-04 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux HighAvailability (v. 8) pcs-0.10.18-2.el8_10.7, pcs-snmp-0.10.18-2.el8_10.7
    • Red Hat Enterprise Linux ResilientStorage (v. 8) pcs-0.10.18-2.el8_10.7, pcs-snmp-0.10.18-2.el8_10.7
  • RHSA-2025:19647 Released 2025-11-04 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability E4S (v.8.8) pcs-0.10.15-4.el8_8.9, pcs-snmp-0.10.15-4.el8_8.9
    • Red Hat Enterprise Linux High Availability TUS (v.8.8) pcs-0.10.15-4.el8_8.9, pcs-snmp-0.10.15-4.el8_8.9
  • RHSA-2025:19512 Released 2025-11-03 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability (v. 9) pcs-0.11.9-2.el9_6.2, pcs-snmp-0.11.9-2.el9_6.2
    • Red Hat Enterprise Linux Resilient Storage (v. 9) pcs-0.11.9-2.el9_6.2, pcs-snmp-0.11.9-2.el9_6.2
  • RHSA-2025:19513 Released 2025-11-03 · Red Hat rating Important
    pcs security update
    • Red Hat Enterprise Linux High Availability (v. 10) cockpit-ha-cluster-0.12.0-3.el10_0.3, pcs-0.12.0-3.el10_0.3, pcs-snmp-0.12.0-3.el10_0.3

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat 3scale API Management Platform 2AffectedNo fix yet
Red Hat Enterprise Linux High Availability (v. 10)Fixed RHSA-2025:19513, RHSA-2025:21036
Red Hat Enterprise Linux High Availability (v. 9)Fixed RHSA-2025:19512, RHSA-2025:20962
Red Hat Enterprise Linux High Availability AUS (v.8.4)Fixed RHSA-2025:19948
Red Hat Enterprise Linux High Availability E4S (v.8.6)Fixed RHSA-2025:19734
Red Hat Enterprise Linux High Availability E4S (v.8.8)Fixed RHSA-2025:19647
Red Hat Enterprise Linux High Availability E4S (v.9.0)Fixed RHSA-2025:19800
Red Hat Enterprise Linux High Availability E4S (v.9.2)Fixed RHSA-2025:19733
Red Hat Enterprise Linux High Availability EUS (v.9.4)Fixed RHSA-2025:19736
Red Hat Enterprise Linux High Availability TUS (v.8.6)Fixed RHSA-2025:19734
Red Hat Enterprise Linux High Availability TUS (v.8.8)Fixed RHSA-2025:19647
Red Hat Enterprise Linux HighAvailability (v. 8)Fixed RHSA-2025:19719
Red Hat Enterprise Linux HighAvailability EUS EXTENSION (v.8.4)Fixed RHSA-2025:19948
Red Hat Enterprise Linux Resilient Storage (v. 9)Fixed RHSA-2025:19512, RHSA-2025:20962
Red Hat Enterprise Linux Resilient Storage E4S (v.9.2)Fixed RHSA-2025:19733
Red Hat Enterprise Linux Resilient Storage EUS (v.9.4)Fixed RHSA-2025:19736
Red Hat Enterprise Linux ResilientStorage (v. 8)Fixed RHSA-2025:19719
Red Hat Enterprise Linux ResilientStorage E4S (v.9.0)Fixed RHSA-2025:19800
Red Hat Enterprise Linux Server HighAvailability (v. 7 ELS)Fixed RHSA-2025:21696
Red Hat Enterprise Linux Server ResilientStorage (v. 7 ELS)Fixed RHSA-2025:21696
Not affected: 10 products
  • Logging Subsystem for Red Hat OpenShift
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat OpenShift AI (RHOAI)
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Dev Spaces
  • Red Hat OpenStack Platform 13 (Queens)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-61770
  2. 2026-10-03 Alias added: GHSA-p543-xpfm-54cp

References

Patch 3

Advisory 2

Other 2

  • TI-2024-16580 Rack ReDos in content type parsing (2nd degree polynomial) CVSS 3.1HIGH 7.5
  • TI-2024-17236 Possible Denial of Service Vulnerability in Rack Header Parsing CVSS 3.1HIGH 7.5
  • TI-2024-17231 Possible DoS Vulnerability with Range Header in Rack CVSS 3.1HIGH 7.5
  • TI-2023-12254 Uncontrolled resource consumption in https://github.com/rack/rack CVSS 3.1HIGH 7.5
  • TI-2025-38165 Rack's multipart parser buffers unbounded per-part headers, enabling DoS (memory exhaustion) CVSS 3.1HIGH 7.5
  • TI-2025-29398 Unbounded-Parameter DoS in Rack::QueryParser CVSS 3.1HIGH 7.5
See all 36 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences