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    CVE-2020-5249

    In Puma (RubyGem) before 4.3.3 and 3.12.4, if an application using Puma allows untrusted input in an early-hints header, an attacker can use a carriage return character to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting. While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS). This is related to CVE-2020-5247, which fixed this vulnerability but only for regular responses. This has been fixed in 4.3.3 and 3.12.4.

    Published:Mar 2, 2020
    Last Modified:Nov 21, 2024
    EPS:Mar 2, 2020
    EPSS Score:0.00498
    CVSS Score:6.5

    Affected Products

    Vendor
    Puma
    Product
    Puma

    Exploits

    No exploit reference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-10 Buffer Overflow via Environment Variables
    CAPEC-101 Server Side Include (SSI) Injection
    CAPEC-105 HTTP Request Splitting
    CAPEC-108 Command Line Execution through SQL Injection
    CAPEC-120 Double Encoding
    CAPEC-13 Subverting Environment Variable Values
    CAPEC-135 Format String Injection
    CAPEC-14 Client-side Injection-induced Buffer Overflow
    CAPEC-209 XSS Using MIME Type Mismatch
    CAPEC-24 Filter Failure through Buffer Overflow
    CAPEC-250 XML Injection
    CAPEC-267 Leverage Alternate Encoding
    CAPEC-273 HTTP Response Smuggling
    CAPEC-28 Fuzzing
    CAPEC-3 Using Leading 'Ghost' Character Sequences to Bypass Input Filters
    CAPEC-31 Accessing/Intercepting/Modifying HTTP Cookies
    CAPEC-34 HTTP Response Splitting
    CAPEC-42 MIME Conversion
    CAPEC-43 Exploiting Multiple Input Interpretation Layers
    CAPEC-45 Buffer Overflow via Symbolic Links
    CAPEC-46 Overflow Variables and Tags
    CAPEC-47 Buffer Overflow via Parameter Expansion
    CAPEC-51 Poison Web Service Registry
    CAPEC-52 Embedding NULL Bytes
    CAPEC-53 Postfix, Null Terminate, and Backslash
    CAPEC-588 DOM-Based XSS
    CAPEC-591 Reflected XSS
    CAPEC-592 Stored XSS
    CAPEC-6 Argument Injection
    CAPEC-63 Cross-Site Scripting (XSS)
    CAPEC-64 Using Slashes and URL Encoding Combined to Bypass Validation Logic
    CAPEC-67 String Format Overflow in syslog()
    CAPEC-7 Blind SQL Injection
    CAPEC-71 Using Unicode Encoding to Bypass Validation Logic
    CAPEC-72 URL Encoding
    CAPEC-76 Manipulating Web Input to File System Calls
    CAPEC-78 Using Escaped Slashes in Alternate Encoding
    CAPEC-79 Using Slashes in Alternate Encoding
    CAPEC-8 Buffer Overflow in an API Call
    CAPEC-80 Using UTF-8 Encoding to Bypass Validation Logic
    CAPEC-83 XPath Injection
    CAPEC-84 XQuery Injection
    CAPEC-85 AJAX Footprinting
    CAPEC-9 Buffer Overflow in Local Command-Line Utilities

    Related CVEs

    CVE-2026-68006 — An issue in Puma v.5.0.0 and before v.8.0.3 allows an attacker to execute arbitrary code via the ext/puma_http…
    CVE-2026-47736 (CVSS 7.5) — Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1…
    CVE-2026-47737 (CVSS 7.5) — 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 …
    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…

    References

    https://github.com/puma/puma/commit/c22712fc93284a45a93f9ad7023888f3a65524f3
    https://github.com/puma/puma/security/advisories/GHSA-33vf-4xgg-9r58
    https://github.com/puma/puma/security/advisories/GHSA-84j7-475p-hp8v
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BMJ3CGZ3DLBJ5WUUKMI5ZFXFJQMXJZIK/
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DIHVO3CQMU7BZC7FCTSRJ33YDNS3GFPK/
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NJ3LL5F5QADB6LM46GXZETREAKZMQNRD/
    https://owasp.org/www-community/attacks/HTTP_Response_Splitting
    https://github.com/puma/puma/commit/c22712fc93284a45a93f9ad7023888f3a65524f3
    https://github.com/puma/puma/security/advisories/GHSA-33vf-4xgg-9r58
    https://github.com/puma/puma/security/advisories/GHSA-84j7-475p-hp8v
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BMJ3CGZ3DLBJ5WUUKMI5ZFXFJQMXJZIK/
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DIHVO3CQMU7BZC7FCTSRJ33YDNS3GFPK/
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NJ3LL5F5QADB6LM46GXZETREAKZMQNRD/
    https://owasp.org/www-community/attacks/HTTP_Response_Splitting

    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