---
id: CVE-2026-55613
title: 'uhttpd: HTTP request smuggling via ubus POST body parse-error desync'
summary: >-
  uhttpd is a small HTTP server. In unpatched repository snapshots,
  `uh_ubus_data_send()` in `ubus.c` can desynchronize HTTP request boundaries
  when a `POST /ubus` JSON body arrives in multiple TCP segments. An initial
  segment completing a…
severity: medium
cvss: 6.9
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-444
vendor: openwrt
product: uhttpd
affected:
  - uhttpd < 7b1bec45826bd78c8afc993435bdc0f1df2fe399
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-11-05T02:55:16.426726Z'
exploitAvailable: true
published: '2026-10-30'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T02:55:37.771Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-55613'
references:
  - url: 'https://github.com/openwrt/uhttpd/security/advisories/GHSA-wgwp-64hh-f52p'
    label: 'https://github.com/openwrt/uhttpd/security/advisories/GHSA-wgwp-64hh-f52p'
  - url: >-
      https://github.com/openwrt/uhttpd/commit/7b1bec45826bd78c8afc993435bdc0f1df2fe399
    label: >-
      https://github.com/openwrt/uhttpd/commit/7b1bec45826bd78c8afc993435bdc0f1df2fe399
  - url: >-
      https://github.com/openwrt/uhttpd/commit/b2285de129b9adc8b12f84f9a27c16c21f2b57a5
    label: >-
      https://github.com/openwrt/uhttpd/commit/b2285de129b9adc8b12f84f9a27c16c21f2b57a5
tags:
  - cve.org
  - exploit-available
epss: 0.00395
epssPercentile: 0.33909
ingestedAt: '2026-11-05T21:36:00.717Z'
---

## Overview

uhttpd is a small HTTP server. In unpatched repository snapshots, `uh_ubus_data_send()` in `ubus.c` can desynchronize HTTP request boundaries when a `POST /ubus` JSON body arrives in multiple TCP segments. An initial segment completing a JSON object sets `du->jsobj`; a later segment takes the existing-object parse-error path and returns zero bytes consumed. The caller neither drains the remaining declared `Content-Length` nor sets `connection_close`. An HTTP request embedded in the unread body suffix is consequently processed as a new request on the same keep-alive connection. The reported reproducer returned a JSON-RPC parse error followed by a second HTTP response. This application-layer body-handler flaw is distinct from Transfer-Encoding header case handling and chunk-length state reset, and affects deployments enabling ubus, including the default OpenWrt configuration and potential proxy/CDN deployments. Repository patches 7b1bec45826bd78c8afc993435bdc0f1df2fe399 and b2285de129b9adc8b12f84f9a27c16c21f2b57a5 address this issue.

## Affected

- `uhttpd < 7b1bec45826bd78c8afc993435bdc0f1df2fe399`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.