uhttpd is a small HTTP server. In unpatched repository snapshots, `client_poll_post_data()` in `client.c` consumes an invalid chunk-length line, such as a size exceeding INT_MAX, then clears `r->content_length` and `r->transfer_chunked` without draining the remaining body or setting `request.connection_close`. The completion check treats the chunked POST as finished and the keep-alive parser returns to `CLIENT_STATE_INIT`. Attacker-controlled body bytes aligned as a complete HTTP request are then parsed and processed as another request on the same connection, causing HTTP request smuggling and request-boundary desynchronization. Commits b78f518478794e16ba3568fc1258e40bf3e8eb3b and 34460b8211d676ef1b9f40d6b775c5e112933690 patch the issue.
History

Tue, 03 Nov 2026 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Openwrt
Openwrt uhttpd
Vendors & Products Openwrt
Openwrt uhttpd

Mon, 02 Nov 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 30 Oct 2026 22:15:00 +0000

Type Values Removed Values Added
Description uhttpd is a small HTTP server. In unpatched repository snapshots, `client_poll_post_data()` in `client.c` consumes an invalid chunk-length line, such as a size exceeding INT_MAX, then clears `r->content_length` and `r->transfer_chunked` without draining the remaining body or setting `request.connection_close`. The completion check treats the chunked POST as finished and the keep-alive parser returns to `CLIENT_STATE_INIT`. Attacker-controlled body bytes aligned as a complete HTTP request are then parsed and processed as another request on the same connection, causing HTTP request smuggling and request-boundary desynchronization. Commits b78f518478794e16ba3568fc1258e40bf3e8eb3b and 34460b8211d676ef1b9f40d6b775c5e112933690 patch the issue.
Title uhttpd vulnerable to HTTP request smuggling via invalid chunk-length state reset
Weaknesses CWE-444
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-10-30T22:00:19.756Z

Updated: 2026-11-02T18:09:13.455Z

Reserved: 2026-06-16T23:31:22.445Z

Link: CVE-2026-55612

cve-icon Vulnrichment

Updated: 2026-11-02T17:03:24.177Z

cve-icon NVD

Status : Deferred

Published: 2026-10-30T22:16:54.950

Modified: 2026-11-02T19:35:33.347

Link: CVE-2026-55612

cve-icon Redhat

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