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.

redhat RHSA-2025:7604: RHSA-2025:7604: Satellite 6.17.0.1 Async Update (Important)

redhat RHSA-2025:7605: RHSA-2025:7605: Satellite 6.16.5.1 Async Update (Important)

The remote SUSE Linux SLES15 / openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2025:01586-1 advisory.

    - CVE-2025-46727: possible memory exhaustion due to unbounded parameter parsing in Rack::QueryParser     (bsc#1242894).
    - CVE-2025-32441: deleted sessions can be restored and occupied by unauthenticated users when the     Rack::Session::Pool       middleware is being used (bsc#1242899).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 24.10 / 25.04 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-7507-1 advisory.

    It was discovered that Rack incorrectly handled deleted rack sessions. An attacker could possibly use this     issue to expose sensitive information or to gain unauthorized access to user accounts. (CVE-2025-32441)

    It was discovered that Rack incorrectly limited the number of parameters in a web request. An attacker     could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 20.04 LTS,     Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 24.10, and Ubuntu 25.04. (CVE-2025-46727)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of the RACK Ruby library installed on the remote host is prior to 2.2.14 / 3.0.16 / 3.1.14 . It is, therefore, affected by a DoS vulnerability where 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.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
237086	SUSE SLES15 / openSUSE 15 Security Update : rubygem-rack (SUSE-SU-2025:01586-1)	Nessus	SuSE Local Security Checks	medium
236870	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 24.10 / 25.04 : Rack vulnerabilities (USN-7507-1)	Nessus	Ubuntu Local Security Checks	medium
236779	Ruby RACK < 2.2.14 / 3.0.16 / 3.1.14 DoS vulnerability	Nessus	Misc.	high

Detections

Analytics

CVE-2025-46727

high

Tenable Plugins

Coming Soon

medium

medium

high