by Kastro
Paper/Archive/CVE-2026-119756

CVE-2026-119756

arendst Tasmota — Tasmota 16.0.0 Heap Out-of-Bounds Write via Device Groups UDP

CVSS 9.8
critical.is priorityof 100
29
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0No EPSS score.000 × 200.0No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Tasmota≤ 16.0.0e97e1e4f7e319a55caa1613aef1f25fc81bdb554CNA

Scores by source

VulnCheck (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

patchgithub.com/arendst/Tasmota/commit/e97e1e4f7e319a55caa1613aef1f25fc81bdb554writeupvulncheck.com/advisories/tasmota-heap-out-of-bounds-write-via-device-groups-udp