CVE-2020-8184 — Vulnerability in rack — CVE Details
Rack allows Percent-encoded cookies to overwrite existing prefixed cookie names
Summary
Advisory Timeline
- First published June 24, 2020 (2301 days ago).
- Last revised September 10, 2026 — 2268 days after initial publication.
Remediation
Upgrade to the fixed version using your package manager.
gem install rack -v 2.1.4
gem install rack -v 2.2.3
After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.
Affected Packages (2)
Affects 1 ecosystem: rubygems (1).
Vulnerability Classification
Common Weakness Enumeration (CWE) identifiers for this vulnerability type.
- CWE-20Improper Input ValidationMITRE
- CWE-784
CVSS Score Breakdown
What the CVSS (Common Vulnerability Scoring System) 7.5 score means for each attack dimension.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
References
- https://nvd.nist.gov/vuln/detail/CVE-2020-8184ADVISORY
- https://github.com/rack/rack/commit/1f5763de6a9fe515ff84992b343d63c88104654cWEB
- https://hackerone.com/reports/895727WEB
- https://github.com/rack/rackPACKAGE
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2020-8184.ymlWEB
- https://groups.google.com/g/rubyonrails-security/c/OWtmozPH9AkWEB
- https://lists.debian.org/debian-lts-announce/2020/07/msg00006.htmlWEB
- https://lists.debian.org/debian-lts-announce/2023/01/msg00038.htmlWEB
- https://usn.ubuntu.com/4561-1WEB
Frequently Asked Questions
- What is CVE-2020-8184?
- Rack allows Percent-encoded cookies to overwrite existing prefixed cookie names This vulnerability has been assigned a severity rating of HIGH (CVSS score: 7.5/10).
- How do I check if my project is affected by CVE-2020-8184?
- CVE-2020-8184 affects rack. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2020-8184 and 200,000+ other known vulnerabilities.
Severity & Exploitability
High exploitability or significant impact. Prioritize remediation within days.
Also Known As
Related CVEs
- CVE-2026-34785HIGH
Rack::Static prefix matching can expose unintended files under the static root
- CVE-2018-16470HIGH
Rack vulnerable to Denial of Service
- CVE-2022-30122HIGH
Denial of Service Vulnerability in Rack Multipart Parsing
- CVE-2026-22860HIGH
Rack has a Directory Traversal via Rack:Directory
- CVE-2025-61770HIGH
Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion)
- CVE-2019-16782MEDIUM
Possible Information Leak / Session Hijack Vulnerability in Rack
- CVE-2026-34831MEDIUM
Rack has Content-Length mismatch in Rack::Files error responses
- CVE-2026-34786MEDIUM
Rack:: Static header_rules bypass via URL-encoded paths
Check if you're affected
Scan your dependencies to see if this vulnerability affects your projects.
Scan Your Dependencies