🛡️ CVE-2024-45614 — puma

🟡 CVSS 5.4 — Medium ✅ No Known Exploit CWE-444 OSV
5.4
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Puma's header normalization allows for client to clobber proxy set headers

Impact

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 trusting headers set by their proxy may be affected. Attackers may be able to downgrade connections to HTTP (non-SSL) or redirect responses, which could cause confidentiality leaks if combined with a separate MITM attack.

Patches

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.

Workarounds

Nginx has a [underscores_in_headers](https://nginx.org/en/docs/http/ngx_http_core_module.html#underscores_in_headers) configuration variable to discard these headers at the proxy level.

Any users that are implicitly trusting the proxy defined headers for security or availability should immediately cease doing so until upgraded to the fixed versions.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. Rated impact: confidentiality none, integrity none, availability none.

Weakness class

CVE-2024-45614 is classified as CWE-444: HTTP Request Smuggling. A proxy and a server disagree on where one request ends, letting an attacker slip a second request past the front end.

Affected software

CVE-2024-45614 is recorded against 1 package.

  • puma (from 6.0.0 up to 6.4.3)

Timeline and source

Published on 20 September 2024 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Web)
github.com (Package)
github.com (Web)
lists.debian.org (Web)
nginx.org (Web)

CVE-2024-45614 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity MEDIUM
CVSS Score 5.4
CVSS Vector CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
CWE CWE-444
Public Exploit ✅ No
Source OSV
Published 2024-09-20
Updated 2026-08-12
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
puma 6.0.0 6.4.3

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