A flaw was found in BusyBox httpd's reverse proxy feature. When the proxy is configured to forward requests matching a URL prefix to a backend server, only the first HTTP request on a TCP connection has its path rewritten. An attacker can send a pipelined second request that is relayed verbatim to the backend, bypassing the configured path restrictions. This allows accessing arbitrary paths on the backend server that were not intended to be exposed through the proxy.
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

Do not use BusyBox httpd P: rules as the sole path-based access control in front of sensitive backends. Remove P: lines if proxying is not required, or place a full reverse proxy (for example nginx or HAProxy) in front of the backend. Recompile with FEATURE_HTTPD_PROXY disabled if the applet is not needed.

History

Wed, 14 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 14 Oct 2026 10:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in BusyBox httpd's reverse proxy feature. When the proxy is configured to forward requests matching a URL prefix to a backend server, only the first HTTP request on a TCP connection has its path rewritten. An attacker can send a pipelined second request that is relayed verbatim to the backend, bypassing the configured path restrictions. This allows accessing arbitrary paths on the backend server that were not intended to be exposed through the proxy.
Title Busybox: busybox: http request smuggling via pipelined requests in httpd reverse proxy
First Time appeared Redhat
Redhat hummingbird
Weaknesses CWE-444
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics cvssV3_1

{'score': 7.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-10-14T10:00:42.946Z

Reserved: 2026-09-10T09:42:04.558Z

Link: CVE-2026-88829

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-14T10:17:57.077

Modified: 2026-10-14T10:17:57.077

Link: CVE-2026-88829

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-14T08:00:00Z

Links: CVE-2026-88829 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses