# CVE-2026-113783: ESP-IDF: Stack-based memory corruption in lwIP DNS/SNTP handling for multi-IP DNS responses

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- espressif / esp-idf: >= 5.2.3, <= 5.2.8 (affected); >= 5.3.2, < 5.3.7 (affected); >= 5.4.0, < 5.4.5 (affected); >= 5.5.0, < 5.5.6 (affected); >= 6.0.0, < 6.0.3 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 7.4 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-121

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/espressif/esp-idf/security/advisories/GHSA-ch63-jxm5-vmvf (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/espressif/esp-idf/commit/75f2ff7e0c2d19e113293ec122b701c83d2f6665 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/espressif/esp-idf/commit/7ab85eb4dc7d7695960d940badcd62592c365056 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/espressif/esp-idf/commit/882843dbf838b0c02e09d46bb6283bda73496b8c (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/espressif/esp-idf/commit/98e6e7a08fca391563651a1e751cc45a3b27d18b (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/espressif/esp-idf/commit/af7543d00a4d7b489e010a70b59fd3d8022a40f4 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/espressif/esp-idf/commit/defaa2f559470acfee5e2e5ea80a79b73424d483 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-113783; retrieved 2026-11-04; source updated 2026-11-04

Revision: 5e9d4abb66cce9165396f1aa01097993dfb87d0d48dfd651b92a75c11fb580c1

Canonical: https://y2.dev/cve/CVE-2026-113783

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