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Vulnerability details: VCID-dh75-6jyw-1ke2
Vulnerability ID VCID-dh75-6jyw-1ke2
Aliases CVE-2026-34827
GHSA-v6x5-cg8r-vv6x
Summary Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Multipart::Parser#handle_mime_head parses quoted multipart parameters such as Content-Disposition: form-data; name="..." using repeated String#index searches combined with String#slice! prefix deletion. For escape-heavy quoted values, this causes super-linear processing. An unauthenticated attacker can send a crafted multipart/form-data request containing many parts with long backslash-escaped parameter values to trigger excessive CPU usage during multipart parsing. This results in a denial of service condition in Rack applications that accept multipart form data. This issue has been patched in versions 3.1.21 and 3.2.6.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-400 Uncontrolled Resource Consumption
CWE-407 Inefficient Algorithmic Complexity
CWE-770 Allocation of Resources Without Limits or Throttling
System Score Found at
cvssv3 7.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-34827.json
epss 0.00041 https://api.first.org/data/v1/epss?cve=CVE-2026-34827
epss 0.00041 https://api.first.org/data/v1/epss?cve=CVE-2026-34827
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2026-34827
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2026-34827
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2026-34827
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2026-34827
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2026-34827
cvssv3.1 7.5 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-v6x5-cg8r-vv6x
cvssv3.1 7.5 https://github.com/rack/rack
generic_textual HIGH https://github.com/rack/rack
cvssv3.1 7.5 https://github.com/rack/rack/security/advisories/GHSA-v6x5-cg8r-vv6x
cvssv3.1_qr HIGH https://github.com/rack/rack/security/advisories/GHSA-v6x5-cg8r-vv6x
generic_textual HIGH https://github.com/rack/rack/security/advisories/GHSA-v6x5-cg8r-vv6x
ssvc Track https://github.com/rack/rack/security/advisories/GHSA-v6x5-cg8r-vv6x
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2026-34827
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2026-34827
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-34827.json
https://api.first.org/data/v1/epss?cve=CVE-2026-34827
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-34827
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://github.com/rack/rack
https://github.com/rack/rack/security/advisories/GHSA-v6x5-cg8r-vv6x
https://nvd.nist.gov/vuln/detail/CVE-2026-34827
2454501 https://bugzilla.redhat.com/show_bug.cgi?id=2454501
GHSA-v6x5-cg8r-vv6x https://github.com/advisories/GHSA-v6x5-cg8r-vv6x
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-34827.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/rack/rack
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/rack/rack/security/advisories/GHSA-v6x5-cg8r-vv6x
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:Y/T:P/P:M/B:A/M:M/D:T/2026-04-02T18:42:04Z/ Found at https://github.com/rack/rack/security/advisories/GHSA-v6x5-cg8r-vv6x
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2026-34827
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.12659
EPSS Score 0.00041
Published At April 4, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-03T07:52:21.365437+00:00 Debian Importer Import https://security-tracker.debian.org/tracker/data/json 38.1.0