HTTP request smuggling in BusyBox httpd reverse proxy
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
The BusyBox httpd reverse proxy rewrites the path only for the first HTTP request on a TCP connection (CWE-444). A remote, unauthenticated attacker can send a pipelined second request that the proxy relays verbatim to the backend, bypassing configured path restrictions and reaching paths that were not meant to be exposed through the proxy.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
The sources list no fixed version for Red Hat Hardened Images.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Hardened Images | Affected | No fix yet |
Timeline
- 2026-10-14 Threatist record created from CVE-2026-88829
- 2026-10-14 Alias added: GHSA-89f7-8rmh-f5q2
- 2026-10-14 Priority changed: MEDIUM → LOW
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-16 Affected versions changed · Red Hat
- 2026-10-16 CVSS score added · Red Hat
References
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Sources
- CVE-2026-88829 · CVE Program
- CVE-2026-88829 · NVD
- FIRST EPSS
- GHSA-89f7-8rmh-f5q2 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-88829 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences