---
id: CVE-2026-113783
title: >-
  ESP-IDF: Stack-based memory corruption in lwIP DNS/SNTP handling for multi-IP
  DNS responses
summary: >-
  ESP-IDF is the Espressif Internet of Things (IOT) Development Framework. From
  5.2.3 until 5.3.7, 5.4.5, 5.5.6, and 6.0.3, the lwIP DNS resolver's
  cached-lookup path in dns_lookup() in dns.c copies every cached address into a
  caller-provi…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-121
vendor: espressif
product: esp-idf
affected:
  - 'esp-idf >= 5.2.3, <= 5.2.8'
  - 'esp-idf >= 5.3.2, < 5.3.7'
  - 'esp-idf >= 5.4.0, < 5.4.5'
  - 'esp-idf >= 5.5.0, < 5.5.6'
  - 'esp-idf >= 6.0.0, < 6.0.3'
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T19:04:16.828Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-113783'
references:
  - url: >-
      https://github.com/espressif/esp-idf/security/advisories/GHSA-ch63-jxm5-vmvf
    label: >-
      https://github.com/espressif/esp-idf/security/advisories/GHSA-ch63-jxm5-vmvf
  - url: >-
      https://github.com/espressif/esp-idf/commit/75f2ff7e0c2d19e113293ec122b701c83d2f6665
    label: >-
      https://github.com/espressif/esp-idf/commit/75f2ff7e0c2d19e113293ec122b701c83d2f6665
  - url: >-
      https://github.com/espressif/esp-idf/commit/7ab85eb4dc7d7695960d940badcd62592c365056
    label: >-
      https://github.com/espressif/esp-idf/commit/7ab85eb4dc7d7695960d940badcd62592c365056
  - url: >-
      https://github.com/espressif/esp-idf/commit/882843dbf838b0c02e09d46bb6283bda73496b8c
    label: >-
      https://github.com/espressif/esp-idf/commit/882843dbf838b0c02e09d46bb6283bda73496b8c
  - url: >-
      https://github.com/espressif/esp-idf/commit/98e6e7a08fca391563651a1e751cc45a3b27d18b
    label: >-
      https://github.com/espressif/esp-idf/commit/98e6e7a08fca391563651a1e751cc45a3b27d18b
  - url: >-
      https://github.com/espressif/esp-idf/commit/af7543d00a4d7b489e010a70b59fd3d8022a40f4
    label: >-
      https://github.com/espressif/esp-idf/commit/af7543d00a4d7b489e010a70b59fd3d8022a40f4
  - url: >-
      https://github.com/espressif/esp-idf/commit/defaa2f559470acfee5e2e5ea80a79b73424d483
    label: >-
      https://github.com/espressif/esp-idf/commit/defaa2f559470acfee5e2e5ea80a79b73424d483
tags:
  - cve.org
ingestedAt: '2026-11-05T21:36:00.518Z'
---

## Overview

ESP-IDF is the Espressif Internet of Things (IOT) Development Framework. From 5.2.3 until 5.3.7, 5.4.5, 5.5.6, and 6.0.3, the lwIP DNS resolver's cached-lookup path in dns_lookup() in dns.c copies every cached address into a caller-provided single ip_addr_t output buffer without a length parameter or bounds check. When CONFIG_LWIP_DNS_MAX_HOST_IP is greater than 1 and a cached hostname has multiple A or AAAA records, a subsequent lookup through dns_gethostbyname() or dns_gethostbyname_addrtype() writes beyond the single-element buffer into adjacent stack memory. A network-positioned attacker who influences DNS responses can cause a reboot through stack-canary corruption or, without stack protection, overwrite stack variables with attacker-controlled address bytes and potentially redirect control flow. This issue is fixed in versions 5.5.6 and 6.0.3 and is scheduled to be fixed in versions 5.3.7 and 5.4.5. No fixed release is available for the end-of-life 5.2 line.

## Affected

- `esp-idf >= 5.2.3, <= 5.2.8`
- `esp-idf >= 5.3.2, < 5.3.7`
- `esp-idf >= 5.4.0, < 5.4.5`
- `esp-idf >= 5.5.0, < 5.5.6`
- `esp-idf >= 6.0.0, < 6.0.3`

## Remediation

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