---
id: "CVE-2026-119053"
kind: "vulnerability"
aliases: ["CVE-2026-119053"]
title: "lwIP SNMP agent: fragmented requests leak adjacent memory in responses"
severity: "medium"
cvss: 6.9
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["embedded", "infrastructure", "iot-firmware", "lwip", "snmp"]
not_affected_if: ["lwip-outside-2.0.0-2.2.1", "snmp-agent-disabled", "snmp-not-network-reachable"]
published_at: "2026-10-29T14:17:52+00:00"
first_seen_at: "2026-10-29T14:25:23+00:00"
updated_at: "2026-10-29T14:25:56+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119053", "first_seen_at": "2026-10-29T14:25:23+00:00"}]
---

# lwIP SNMP agent: fragmented requests leak adjacent memory in responses

lwIP versions 2.0.0 through 2.2.1, built with the SNMP agent enabled, copy too many bytes when handling fragmented SNMP requests. A remote attacker who knows the read community string can get adjacent receive-buffer or pool memory echoed back in responses.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check whether the build includes the lwIP SNMP agent (`LWIP_SNMP` enabled in the lwIP configuration)
- Check the lwIP version in the firmware or source tree against `2.0.0` through `2.2.1`

## Timeline

- 2026-10-29T14:25:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119053

## From the sources

lwIP 2.0.0 through 2.2.1 built with the SNMP agent contains an out-of-bounds read vulnerability in snmp_pbuf_stream_writeto() that bounds copies by pbuf->len instead of remaining bytes. Remote unauthenticated attackers knowing the read community can send fragmented SNMP requests to receive adjacent receive-buffer or pool memory echoed in responses.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_