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Fencer Intel
medium 5.3

CVE-2026-125110 json

Rack: Rack::Static header_rules bypass via dot-segment normalization mismatch

published 2d ago modified yesterday also EUVD-2026-120484 , GHSA-wvg4-6p58-3gh3

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 16%
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::Static serves a path after Utils.clean_path_info normalization but evaluates header_rules against a path that is only URL-decoded. An unauthenticated attacker can request a known file through raw or percent-encoded dot segments and receive it without path-specific security headers such as Content-Disposition or Content-Security-Policy. Applications that do not use path-specific header_rules are not affected. 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-2026-125110

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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-2026-125110 updated cvss 5.3

rack: rack: Security header bypass via unnormalized dot segments in request paths

  • 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

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/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
  • CWE-180 Incorrect Behavior Order: Validate Before Canonicalize

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.