CVE-2026-55612

LOW
INFO Priority: 0.01 BB Relevance: 57/100
Published: 2026-10-30 Modified: 2026-10-30 First seen: 2026-10-30 Status: active

Attack Surface

Network No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: High
PR: None
UI: None
S: Unchanged
C: None
I: Low
A: None

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.

Weakness Classification (1)

Affected Software (2)

VendorProductVersion
openwrt uhttpd >= b7c85a2819b3869279a669d5681f574824589c6c, < b78f518478794e16ba3568fc1258e40bf3e8eb3b
openwrt uhttpd >= b7c85a2819b3869279a669d5681f574824589c6c, < 34460b8211d676ef1b9f40d6b775c5e112933690

Bug Bounty Relevance

57 / 100
✓ Network accessible
✓ No authentication
✓ No user interaction

CVSS Score

3.7 / 10.0 v3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS — Exploitation Probability

0.29%
Raw Score 0.002900
Percentile 21.6%
Date 2026-10-31

Intelligence Sources

mitre ref →
nvd ref →