Tasmota: Heap out-of-bounds write in SendReceiveDeviceGroupMessage (CVE-2026-119756)
Tasmota versions through 16.0.0 contain a heap out-of-bounds write vulnerability in the SendReceiveDeviceGroupMessage() function that allows unauthenticated local network attackers to trigger memory corruption via crafted UDP packets.
CVE search metadata
CVE search record: CVE-2026-119756. Severity: critical. CVSS: 9.8. KEV: no. Product: Tasmota (<= 16.0.0). Brief: Tasmota: Heap out-of-bounds write in SendReceiveDeviceGroupMessage (CVE-2026-119756). Brief link: https://feed.craftedsignal.io/briefs/2026-11-tasmota-oob-write/
Triage facts
Revision 1- Applicability
- Tasmota (<= 16.0.0)
- Evidence
- Unknown
- Severity
- Critical
- Sources
- 1 public source
- Freshness
- Revision 1Nov 9, 19:50 UTC
- Vulnerabilities
- 1 CVE
- Source quality
- A2Roughly even chance
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. This causes 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.