CVE-2020-25613

Name: CVE-2020-25613
Creator: NVD / NIST
Published: 2020-10-06T13:15:13.823+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 3.77%

Last modified Jun 17, 2026

CVE-2020-25613 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. EPSS estimates a 3.77% chance of exploitation in the next 30 days.

Description

An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypass a reverse proxy (which also has a poor header check), which may lead to an HTTP Request Smuggling attack.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

3.77%

88.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-444

Affected Software

Vendor	Product	Versions
Ruby-Lang	Ruby	<= 2.5.8
Ruby-Lang	Ruby	>= 2.6.0, <= 2.6.6
Ruby-Lang	Ruby	>= 2.7.0, <= 2.7.1
Ruby-Lang	Webrick	<= 1.6.0
Fedoraproject	Fedora	32
Fedoraproject	Fedora	33

References

https://github.com/ruby/webrick/commit/8946bb38b4d87549f0d99ed73c62c41933f97cc7Patch, Third Party Advisory
https://hackerone.com/reports/965267Permissions Required, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/04/msg00033.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PFP3E7KXXT3H3KA6CBZPUOGA5VPFARRJ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YTZURYROG3FFED3TYCQOBV66BS4K6WOV/
https://security.gentoo.org/glsa/202401-27
https://security.netapp.com/advisory/ntap-20210115-0008/Third Party Advisory
https://www.ruby-lang.org/en/news/2020/09/29/http-request-smuggling-cve-2020-25613/Vendor Advisory
https://github.com/ruby/webrick/commit/8946bb38b4d87549f0d99ed73c62c41933f97cc7Patch, Third Party Advisory
https://hackerone.com/reports/965267Permissions Required, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/04/msg00033.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PFP3E7KXXT3H3KA6CBZPUOGA5VPFARRJ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YTZURYROG3FFED3TYCQOBV66BS4K6WOV/
https://security.gentoo.org/glsa/202401-27
https://security.netapp.com/advisory/ntap-20210115-0008/Third Party Advisory
https://www.ruby-lang.org/en/news/2020/09/29/http-request-smuggling-cve-2020-25613/Vendor Advisory

Timeline

Published: Oct 6, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-25613?

How severe is CVE-2020-25613?

CVE-2020-25613 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 3.77% probability of exploitation in the next 30 days.

How do I fix CVE-2020-25613?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-25613?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST