Rack is a modular Ruby web server interface. Prior to versions 2.2.14, 3.0.16, and 3.1.14, `Rack::QueryParser` parses query strings and `application/x-www-form-urlencoded` bodies into Ruby data structures without imposing any limit on the number of parameters, allowing attackers to send requests with extremely large numbers of parameters. The vulnerability arises because `Rack::QueryParser` iterates over each `&`-separated key-value pair and adds it to a Hash without enforcing an upper bound on the total number of parameters. This allows an attacker to send a single request containing hundreds of thousands (or more) of parameters, which consumes excessive memory and CPU during parsing. An attacker can trigger denial of service by sending specifically crafted HTTP requests, which can cause memory exhaustion or pin CPU resources, stalling or crashing the Rack server. This results in full service disruption until the affected worker is restarted. Versions 2.2.14, 3.0.16, and 3.1.14 fix the issue. Some other mitigations are available. One may use middleware to enforce a maximum query string size or parameter count, or employ a reverse proxy (such as Nginx) to limit request sizes and reject oversized query strings or bodies. Limiting request body sizes and query string lengths at the web server or CDN level is an effective mitigation.
This issue has been addressed in the following products: Red Hat Satellite 6.17 for RHEL 9 Via RHSA-2025:7604 https://access.redhat.com/errata/RHSA-2025:7604
This issue has been addressed in the following products: Red Hat Satellite 6.16 for RHEL 8 Red Hat Satellite 6.16 for RHEL 9 Via RHSA-2025:7605 https://access.redhat.com/errata/RHSA-2025:7605
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2025:8254 https://access.redhat.com/errata/RHSA-2025:8254
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2025:8256 https://access.redhat.com/errata/RHSA-2025:8256
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.8 Extended Update Support Via RHSA-2025:8279 https://access.redhat.com/errata/RHSA-2025:8279
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions Red Hat Enterprise Linux 8.6 Telecommunications Update Service Via RHSA-2025:8290 https://access.redhat.com/errata/RHSA-2025:8290
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions Via RHSA-2025:8291 https://access.redhat.com/errata/RHSA-2025:8291
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Extended Update Support Via RHSA-2025:8289 https://access.redhat.com/errata/RHSA-2025:8289
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.4 Extended Update Support Via RHSA-2025:8288 https://access.redhat.com/errata/RHSA-2025:8288
This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2025:8319 https://access.redhat.com/errata/RHSA-2025:8319
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Extended Lifecycle Support Via RHSA-2025:8322 https://access.redhat.com/errata/RHSA-2025:8322
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.4 Telecommunications Update Service Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions Via RHSA-2025:8323 https://access.redhat.com/errata/RHSA-2025:8323
This issue has been addressed in the following products: Red Hat Satellite 6.15 for RHEL 8 Via RHSA-2025:9838 https://access.redhat.com/errata/RHSA-2025:9838