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Fencer Intel
low 3.7

CVE-2026-125108 json

Rack: Multipart boundary ambiguity guard in Rack::Multipart::Parser can be bypassed with a quoted boundary value, allowing WAF bypass

published 2d ago modified yesterday also EUVD-2026-120481 , GHSA-p8x9-v4hv-2w4g

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

Rack is a modular Ruby web server interface. Prior to 2.2.25, 3.1.23, and 3.2.8, Rack::Multipart::Parser.parse_boundary can skip a leading empty or quoted boundary parameter in a multipart Content-Type header and accept a later parameter. Rack can therefore parse a request body with a boundary that a conforming intermediary would not derive, allowing form fields or file uploads to reach an application without the intended proxy or web application firewall inspection. This issue is fixed in versions 2.2.25, 3.1.23, and 3.2.8.

Patch / fix

  • rubygems rack 2.2.25, 3.1.23, 3.2.8
  • ruby-rack Debian 14 3.2.8-1

debian advisories DEBIAN-CVE-2026-125108

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-125108 updated cvss 3.7

rack: rack: Security inspection bypass via multipart boundary parsing differential

  • Red Hat 3scale API Management Platform 2 3scale-amp2/zync-rhel9, 3scale-amp2/system-rhel8, 3scale-amp2/system-rhel9, 3scale-amp2/backend-rhel8
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 pcs, pcs-snmp, python-clufter, pcs 0.12.3-3.el10 Red Hat Enterprise Linux 8 pcs, pcs-snmp, pcs 0.12.3-3.el10 Red Hat Enterprise Linux 9 pcs, pcs-snmp, pcs 0.12.3-3.el10 Red Hat Enterprise Linux 10 pcs 0.12.3-3.el10
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenStack Platform 13 (Queens) rhosp13/openstack-redis, rhosp13/openstack-haproxy, rhosp13/openstack-mariadb, rhosp13/openstack-rabbitmq, rhosp13/openstack-ovn-northd, rhosp13/openstack-manila-share, +2 more Red Hat OpenStack Platform 16.2 rhosp-rhel8/openstack-redis, rhosp-rhel8/openstack-haproxy, rhosp-rhel8/openstack-mariadb, rhosp-rhel8/openstack-rabbitmq, rhosp-rhel8/openstack-ovn-northd, rhosp-rhel8/openstack-manila-share, +2 more Red Hat OpenStack Platform 17.1 rhosp-rhel9/openstack-redis, rhosp-rhel9/openstack-haproxy, rhosp-rhel9/openstack-mariadb, rhosp-rhel9/openstack-rabbitmq, rhosp-rhel9/openstack-ovn-northd, rhosp-rhel9/openstack-manila-share, +2 more
    affected: workaround, no fix planned “Out of support scope”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
rubygems rack
<2.2.25
>=3.0.0, <3.1.23
>=3.2.0, <3.2.8
2.2.25
3.1.23
3.2.8

Affected products

  • rack rack

Classification

Weakness

References

Sources

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