Puma Fixes Underscore Header Vulnerability
Key Information
- Vendor
- Puma
- Status
- Puma
- Vendor
- CVE Published:
- 19 September 2024
Badges
Summary
Puma is a Ruby/Rack web server built for parallelism. In affected versions clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users relying on proxy set variables is affected. v6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win. Users are advised to upgrade. Nginx has a underscores_in_headers configuration variable to discard these headers at the proxy level as a mitigation. Any users that are implicitly trusting the proxy defined headers for security should immediately cease doing so until upgraded to the fixed versions.
Affected Version(s)
puma < 6.0.0, 6.4.3
puma < 5.6.9
Exploit Proof of Concept (PoC)
PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.
CVSS V3.1
Timeline
- 👾
Exploit exists.
Vulnerability published.
Vulnerability Reserved.