CVE-2025-59830

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Moderate Moderate Impact What does this mean?
7.5 CVSS v3 Base Score

Description

An unsafe default behavior in Rack::QueryParser allows bypass of the params_limit parameter count restriction when query string parameters are delimited by semicolons (;) rather than ampersands (&). The parser counts only & when enforcing the limit, while still splitting on both & and ;. As a result, an attacker can supply a crafted HTTP query using ; delimiters to exceed the intended parameter count, potentially causing performance degradation or exhaustion of resources (denial of service).

Statement

The overall severity of this flaw is Moderate, because most Rack applications are not directly impacted. The vulnerability primarily affects applications or middleware that invoke Rack::QueryParser directly using its default configuration, which accepts both & and ; as parameter delimiters. This behavior can lead to excessive CPU or memory consumption, resulting only a limited denial-of-service condition.

For typical applications using Rack::Request, the default request-handling flow applies safe parsing logic and does not exhibit the vulnerable behavior.

In summary, while the theoretical severity is High, the practical impact is generally Moderate to Low for standard configurations.

Affectedness:

It should be noted that starting from Rack v3.x, the framework no longer splits query parameters on semicolons. This change was introduced in commit ef1fc0c44e6a4b77c8fcf9b4f3bfa09f04ae8482, effectively mitigating this issue in newer releases.

Rack 1.x is also not affected by this vulnerability. The vulnerable parsing logic was introduced in Rack 2.x; earlier versions use a simpler query parsing mechanism that does not expose the same resource exhaustion risk.

Additionally, Ruby 2.x and 3.x versions shipped with Red Hat Enterprise Linux are not affected, as they do not bundle the rack RubyGem by default. Rack is a third-party gem that must be installed separately.

Mitigation

No action is required for typical Rack applications that use the framework’s default request-handling mechanisms, as these are not impacted.

For custom implementations or middleware that directly invoke Rack::QueryParser, administrators should:

Use explicit delimiters: Configure QueryParser to use a specific delimiter (e.g. &) rather than accepting both & and ;.

Limit request size and parameters: Enforce request size and parameter count limits at upstream layers (such as a web server, reverse proxy, or WAF) to prevent excessive resource consumption.

Prefer safe APIs: Use Rack::Request or other higher-level request parsing APIs, which apply safe defaults and avoid this vulnerability.

Additional Information

External References

Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2025-59830

Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2025-59830

Content from github.com is not included.https://github.com/rack/rack/commit/54e4ffdd5affebcb0c015cc6ae74635c0831ed71

Content from github.com is not included.https://github.com/rack/rack/security/advisories/GHSA-625h-95r8-8xpm

Affected Packages and Issued Red Hat Security Errata

Products / Services Components State Errata
Logging Subsystem for Red Hat OpenShift openshift-logging/cluster-logging-operator-bundle Not affected
Logging Subsystem for Red Hat OpenShift openshift-logging/cluster-logging-rhel9-operator Not affected
Logging Subsystem for Red Hat OpenShift openshift-logging/eventrouter-rhel9 Not affected
Logging Subsystem for Red Hat OpenShift openshift-logging/fluentd-rhel8 Not affected
Logging Subsystem for Red Hat OpenShift openshift-logging/fluentd-rhel9 Not affected
Logging Subsystem for Red Hat OpenShift openshift-logging/log-file-metric-exporter-rhel9 Not affected
Logging Subsystem for Red Hat OpenShift openshift-logging/logging-view-plugin-rhel9 Not affected
Logging Subsystem for Red Hat OpenShift openshift-logging/vector-rhel9 Not affected
OpenShift Service Mesh 2 openshift-service-mesh/grafana-rhel8 Out of support scope
OpenShift Service Mesh 2 openshift-service-mesh/istio-cni-rhel8 Out of support scope
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).

CVSS v3 Score Breakdown Red Hat NVD
CVSS v3 Base Score 7.5
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact None
Availability Impact High

CVSS v3 Vector

Red Hat CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

 For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

What can I do if my product is listed as "Will not fix"?

 A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

 A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

 A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

 The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

 In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our This content is not included.Red Hat Vulnerability Scanner Certification program.

My product is listed as "Out of Support Scope". What does this mean?

 When a product is listed as "Out of Support Scope", it means a vulnerability with the impact level assigned to this CVE is no longer covered by its current support lifecycle phase. The product has been identified to contain the impacted component, but analysis to determine whether it is affected or not by this vulnerability was not performed. The product should be assumed to be affected. Customers are advised to apply any mitigation options documented on this page, consider removing or disabling the impacted component, or upgrade to a supported version of the product that has an update available.