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    CVE-2021-22959

    The parser in accepts requests with a space (SP) right after the header name before the colon. This can lead to HTTP Request Smuggling (HRS) in llhttp < v2.1.4 and < v6.0.6.

    Published:Oct 12, 2021
    Last Modified:Apr 30, 2025
    EPS:Nov 15, 2021
    EPSS Score:0.00186
    CVSS Score:6.5

    Affected Products

    Vendor
    Debian
    Product
    Debian Linux
    Vendor
    Llhttp
    Product
    Llhttp
    Vendor
    Oracle
    Product
    Graalvm
    Vendor
    Redhat
    Product
    Enterprise Linux
    Vendor
    Redhat
    Product
    Rhel E4s
    Vendor
    Redhat
    Product
    Rhel Eus
    Vendor
    Redhat
    Product
    Rhel Software Collections

    Exploits

    https://hackerone.com/reports/1238709https://hackerone.com/reports/1238709

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-273 HTTP Response Smuggling
    CAPEC-33 HTTP Request Smuggling

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    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