Buffer overflow in Espressif Esp-Idf
CVE-2026-113783
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.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Espressif Esp-Idf — versions >= 5.2.3, <= 5.2.8, >= 5.3.2, < 5.3.7, >= 5.4.0, < 5.4.5
Weakness classification (CWE)
References
- https://github.com/espressif/esp-idf/commit/75f2ff7e0c2d19e113293ec122b701c83d2f6665
- https://github.com/espressif/esp-idf/commit/7ab85eb4dc7d7695960d940badcd62592c365056
- https://github.com/espressif/esp-idf/commit/882843dbf838b0c02e09d46bb6283bda73496b8c
- https://github.com/espressif/esp-idf/commit/98e6e7a08fca391563651a1e751cc45a3b27d18b
- https://github.com/espressif/esp-idf/commit/af7543d00a4d7b489e010a70b59fd3d8022a40f4
- https://github.com/espressif/esp-idf/commit/defaa2f559470acfee5e2e5ea80a79b73424d483
- https://github.com/espressif/esp-idf/security/advisories/GHSA-ch63-jxm5-vmvf
Frequently asked questions
- What is CVE-2026-113783?
- CVE-2026-113783 is a high-severity vulnerability in Espressif Esp-Idf, classified under Stack-based Buffer Overflow. CVSS score: 7.4/10. Published 2026-11-04.
- How severe is CVE-2026-113783?
- High severity. CVSS v3 base score is 7.4 out of 10.