Vulnerability in Arendst Tasmota
CVE-2026-119756
Tasmota through 16.0.0, fixed in commit e97e1e4, contains a heap out-of-bounds write vulnerability in SendReceiveDeviceGroupMessage() that allows unauthenticated attackers on the local network to corrupt heap memory by sending crafted Device Groups messages over UDP port 4447 that cause the log_remaining counter to go negative and writes to exceed the fixed 512-byte buffer. Attackers can exploit this flaw to crash the device or potentially achieve native code execution on ESP8266 and ESP32 platforms that lack ASLR and heap cookies.
Published .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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
Weakness classification (CWE)
References
- Patch Commit (issue-tracking, patch)
- VulnCheck Advisory: Tasmota 16.0.0 Heap Out-of-Bounds Write via Device Groups UDP (third-party-advisory)
Frequently asked questions
- What is CVE-2026-119756?
- CVE-2026-119756 is a critical-severity vulnerability in Arendst Tasmota, classified under Buffer Access with Incorrect Length Value. CVSS score: 9.8/10. Published 2026-11-09.
- How severe is CVE-2026-119756?
- Critical severity. CVSS v3 base score is 9.8 out of 10.