CVE-2026-47737
High
Description
Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, Puma is vulnerable to source IP spoofing when set_remote_address proxy_protocol: :v1 is enabled and persistent connections are used because Puma incorrectly re-parses PROXY protocol headers after each keep-alive request on the same connection, allowing an attacker to inject a second PROXY header and overwrite REMOTE_ADDR. This issue is fixed in versions 7.2.1 and 8.0.2.
SeverityHigh
CVSS7.5
Exploit probability—
Product
Puma
PublishedJul 14, 2026
First seenJul 14, 2026
Weakness typeCWE-290CWE-290CWE-345CWE-345
How to fix
Update
- puma8.0.2, 7.2.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| pumaRubyGems | 8.0.0 ≤ v < 8.0.2, 5.5.0 ≤ v < 7.2.1 | 8.0.2, 7.2.1 |
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