MediumCVE-2025-61780

    Rack has Possible Information Disclosure Vulnerability (CVE-2025-61780)

    Published Last modified Sources: Debian LTS, Debian, OSV, CVE.org

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    What is affected, what to do

    Rack is a modular Ruby web server interface. Prior to versions 2.2.20, 3.1.18, and 3.2.3, a possible information disclosure vulnerability existed in `Rack::Sendfile` when running behind a proxy that supports `x-sendfile` headers (such as Nginx).

    Update Rack to version 2.2.20.

    Affected
    • Rack gte 3.0, < 3.1.18..*
    • Rack lt *..2.2.20
    Fixed in
    • Rack 2.2.20

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    5.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    5.8

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: Debian LTS, Debian, OSV, CVE.org

    0.5 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 46.3

    Show all metrics
    Severity
    Medium
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    57.40 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    5.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    5.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.5 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    46.3
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 10 October 2025
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-200, CWE-441, CWE-913

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Rack is a modular Ruby web server interface. Prior to versions 2.2.20, 3.1.18, and 3.2.3, a possible information disclosure vulnerability existed in `Rack::Sendfile` when running behind a proxy that supports `x-sendfile` headers (such as Nginx). Specially crafted headers could cause `Rack::Sendfile` to miscommunicate with the proxy and trigger unintended internal requests, potentially bypassing proxy-level access restrictions. When `Rack::Sendfile` received untrusted `x-sendfile-type` or `x-accel-mapping` headers from a client, it would interpret them as proxy configuration directives. This could cause the middleware to send a "redirect" response to the proxy, prompting it to reissue a new internal request that was not subject to the proxy's access controls. An attacker could exploit this by setting a crafted `x-sendfile-type: x-accel-redirect` header, setting a crafted `x-accel-mapping` header, and requesting a path that qualifies for proxy-based acceleration. Attackers could bypass proxy-enforced restrictions and access internal endpoints intended to be protected (such as administrative pages). The vulnerability did not allow arbitrary file reads but could expose sensitive application routes. This issue only affected systems meeting all of the following conditions: The application used `Rack::Sendfile` with a proxy that supports `x-accel-redirect` (e.g., Nginx); the proxy did **not** always set or remove the `x-sendfile-type` and `x-accel-mapping` headers; and the application exposed an endpoint that returned a body responding to `.to_path`. Users should upgrade to Rack versions 2.2.20, 3.1.18, or 3.2.3, which require explicit configuration to enable `x-accel-redirect`. Alternatively, configure the proxy to always set or strip the header, or in Rails applications, disable sendfile completely.

    Source: Debian LTS Advisories, Debian Security Advisories, OSV (Open Source Vulnerabilities), NVD (NIST), CVE.org (MITRE), cvelistv5

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    rackrack
    • ≥ 3.0, < 3.1.18
    • < 2.2.20
    • 3.0.0 – < 3.1.18
    • 3.2.0 – < 3.2.3
    • < 2.2.20
    • —
    • 2.2.20
    • 3.1.18
    • 3.2.3
    • 2.2.20
    rubygemsrack
    • 3.1.12
    • 3.0.6
    • 3.0.12
    • 1.6.8
    • 3.1.11
    • 3.0.4.1
    • 2.2.6.3
    • 3.0.4.2
    • 2.0.7
    • 2.0.4
    • 1.3.9
    • 1.1.1.pre
    • 1.4.2
    • 1.6.4
    • 2.2.6
    • 1.4.6
    • 1.3.7
    • 2.2.11
    • 2.0.9.2
    • 1.6.3
    • 1.2.5
    • 2.2.6.2
    • 2.2.5
    • 2.0.1
    • 2.2.2
    • 2.2.19
    • 1.2.2
    • 3.0.1
    • 2.2.16
    • 3.1.17
    • 1.5.0.beta.1
    • 2.2.18
    • 3.1.8
    • 3.1.14
    • 1.4.7
    • 1.3.8
    • 3.0.15
    • 1.2.7
    • 1.5.2
    • 2.2.0
    • 0.9.0
    • 0.4.0
    • 3.1.3
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    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianruby-rackbookworm
    Linuxdebianruby-rackbullseye
    Linuxdebianruby-racktrixie

    Weakness classes (CWE)

    • CWE-200Exposure of Sensitive Information to an Unauthorized Actor

      Class

      The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

      Entry at MITRE CWE-200

    • CWE-441Unintended Proxy or Intermediary ('Confused Deputy')

      Class

      The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.

      Entry at MITRE CWE-441

    • CWE-913Improper Control of Dynamically-Managed Code Resources

      Class

      The product does not properly restrict reading from or writing to dynamically-managed code resources such as variables, objects, classes, attributes, functions, or executable instructions or statements.

      Entry at MITRE CWE-913

    References & sources

    • github.comrack/rack/security/advisories/GHSA-r657-rxjc-j557web, x_refsource_CONFIRM, Mitigation, Vendor advisory
    • NVD (NIST)vuln/detail/CVE-2025-61780advisory
    • github.comrack/rack/commit/57277b7741581fa827472c5c666f6e6a33abd784web, x_refsource_MISC, Patch
    • github.comrack/rack/commit/7e69f65eefe9cd2868df9f9f3b0977b86f93523aweb, x_refsource_MISC, Patch
    • github.comrack/rack/commit/fba2c8bc63eb787ff4b19bc612d315fda6126d85web, x_refsource_MISC, Patch
    • github.comrack/rackpackage
    • github.comrubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2025-61780.y…web

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    One NVD translation into another language is hidden.

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