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    CVE-2026-47737

    Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, Puma is vulnerable to source IP spoofing when set_remote_address proxy_protocol: :v1 is enabled and persistent connections are used because Puma incorrectly re-parses PROXY protocol headers after each keep-alive request on the same connection, allowing an attacker to inject a second PROXY header and overwrite REMOTE_ADDR. This issue is fixed in versions 7.2.1 and 8.0.2.

    Published:Jul 14, 2026
    Last Modified:Jul 15, 2026
    EPS:Jul 14, 2026
    EPSS Score:0.00177
    CVSS Score:7.5

    Affected Products

    Vendor
    Puma
    Product
    Puma

    Exploits

    No exploit reference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-111 JSON Hijacking (aka JavaScript Hijacking)
    CAPEC-141 Cache Poisoning
    CAPEC-142 DNS Cache Poisoning
    CAPEC-148 Content Spoofing
    CAPEC-21 Exploitation of Trusted Identifiers
    CAPEC-218 Spoofing of UDDI/ebXML Messages
    CAPEC-22 Exploiting Trust in Client
    CAPEC-384 Application API Message Manipulation via Man-in-the-Middle
    CAPEC-385 Transaction or Event Tampering via Application API Manipulation
    CAPEC-386 Application API Navigation Remapping
    CAPEC-387 Navigation Remapping To Propagate Malicious Content
    CAPEC-388 Application API Button Hijacking
    CAPEC-459 Creating a Rogue Certification Authority Certificate
    CAPEC-461 Web Services API Signature Forgery Leveraging Hash Function Extension Weakness
    CAPEC-473 Signature Spoof
    CAPEC-476 Signature Spoofing by Misrepresentation
    CAPEC-59 Session Credential Falsification through Prediction
    CAPEC-60 Reusing Session IDs (aka Session Replay)
    CAPEC-665 Exploitation of Thunderbolt Protection Flaws
    CAPEC-667 Bluetooth Impersonation AttackS (BIAS)
    CAPEC-701 Browser in the Middle (BiTM)
    CAPEC-94 Adversary in the Middle (AiTM)

    Related CVEs

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    CVE-2024-45614 (CVSS 5.4) — Puma is a Ruby/Rack web server built for parallelism. In affected versions clients could clobber values set by…
    CVE-2024-21647 (CVSS 5.9) — Puma is a web server for Ruby/Rack applications built for parallelism. Prior to version 6.4.2, puma exhibited …
    CVE-2023-40175 (CVSS 7.3) — Puma is a Ruby/Rack web server built for parallelism. Prior to versions 6.3.1 and 5.6.7, puma exhibited incorr…
    CVE-2022-24790 (CVSS 9.1) — Puma is a simple, fast, multi-threaded, parallel HTTP 1.1 server for Ruby/Rack applications. When using Puma b…
    CVE-2022-23634 (CVSS 8) — Puma is a Ruby/Rack web server built for parallelism. Prior to `puma` version `5.6.2`, `puma` may not always c…
    CVE-2021-41136 (CVSS 3.7) — Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to versions 5.5.1 and 4.3.9, using `puma` with a p…
    CVE-2021-29509 (CVSS 7.5) — Puma is a concurrent HTTP 1.1 server for Ruby/Rack applications. The fix for CVE-2019-16770 was incomplete. Th…
    CVE-2020-11076 (CVSS 7.5) — In Puma (RubyGem) before 4.3.4 and 3.12.5, an attacker could smuggle an HTTP response, by using an invalid tra…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High