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Vulnerability · Published Nov 4, 2026 · Assigned by GitHub_M

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

High 7.4

In plain English

A high-severity stack buffer overflow in esp-idf from espressif. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities).

Severity (CVSS 3.1)7.4High
Exploit odds (30 days)0.4%top 71.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

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 products (as reported)

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

Weakness: CWE-121 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

References