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Linux Distros Unpatched Vulnerability : CVE-2026-34830

🗓️ 04 Apr 2026 00:00:00Reported by TenableType 
nessus
 nessus
🔗 www.tenable.com

Rack vulnerability CVE-2026-34830 enables regex injection via X-Accel-Mapping in Rack::Sendfile.

Related
Refs
Code
ReporterTitlePublishedViews
Family
ATTACKERKB
CVE-2026-34830
2 Apr 202616:47
attackerkb
Chainguard
CVE-2026-34830 vulnerabilities
6 Apr 202601:18
cgr
CNNVD
Rack 安全漏洞
2 Apr 202600:00
cnnvd
CVE
CVE-2026-34830
2 Apr 202616:47
cve
Cvelist
CVE-2026-34830 Rack: Rack::Sendfile regex injection via HTTP_X_ACCEL_MAPPING header allows arbitrary file reads through nginx
2 Apr 202616:47
cvelist
Debian CVE
CVE-2026-34830
2 Apr 202616:47
debiancve
EUVD
EUVD-2026-18390
2 Apr 202620:35
euvd
Github Security Blog
Rack::Sendfile header-based X-Accel-Mapping regex injection enables unauthorized X-Accel-Redirect
2 Apr 202620:35
github
NVD
CVE-2026-34830
2 Apr 202617:16
nvd
OSV
CGA-5926-72FF-MP26
6 Apr 202600:30
osv
Rows per page
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(304836);
  script_version("1.10");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/22");

  script_cve_id("CVE-2026-34830");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-34830");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6,
    Rack::Sendfile#map_accel_path interpolates the value of the X-Accel-Mapping request header directly into a
    regular expression when rewriting file paths for X-Accel-Redirect. Because the header value is not
    escaped, an attacker who can supply X-Accel-Mapping to the backend can inject regex metacharacters and
    control the generated X-Accel-Redirect response header. In deployments using Rack::Sendfile with x-accel-
    redirect, this can allow an attacker to cause nginx to serve unintended files from configured internal
    locations. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6. (CVE-2026-34830)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2026-34830");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-34830");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-34830");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-34830");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/04/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/04");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:7");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:8");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:8");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:9");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ruby-rack");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:cockpit-ha-cluster");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pcs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pcs-snmp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:python-clufter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:ruby-rack");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:cockpit-ha-cluster");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:pcs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:pcs-snmp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python-clufter");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/CentOS Linux-7", "Host/OS/CentOS Linux-8", "Host/OS/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Red Hat Enterprise Linux-10", "Host/OS/Red Hat Enterprise Linux-7", "Host/OS/Red Hat Enterprise Linux-8", "Host/OS/Red Hat Enterprise Linux-9", "Host/OS/Ubuntu Linux-14.04");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/CentOS/rpm-list")) && empty_or_null(get_one_kb_item("Host/Debian/dpkg-l")) && empty_or_null(get_one_kb_item("Host/RedHat/rpm-list"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "ruby-rack"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "ruby-rack"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "ruby-rack"}
        ]
      }
    ]
  },
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "ruby-rack"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "cockpit-ha-cluster"},
          {"reference": "pcs"},
          {"reference": "pcs-snmp"}
        ]
      }
    ]
  },
  "CentOS Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "pcs"},
          {"reference": "pcs-snmp"},
          {"reference": "python-clufter"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "pcs"},
          {"reference": "pcs-snmp"},
          {"reference": "python-clufter"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "pcs"},
          {"reference": "pcs-snmp"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "pcs"},
          {"reference": "pcs-snmp"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "pcs"},
          {"reference": "pcs-snmp"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}

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22 May 2026 00:00Current
5.8Medium risk
Vulners AI Score5.8
CVSS 3.15.9 - 7.5
EPSS0.00047
SSVC
0