CVE-2026-119756 (CVSS 9.8)

Description

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.

Is your site exposed to CVE-2026-119756?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0049

Probability of exploitation

0.43%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-805 CWE-805

References

Other References

https://github.com/arendst/Tasmota/commit/e97e1e4f7e319a55caa1613aef1f25fc81bdb554 https://www.vulncheck.com/advisories/tasmota-heap-out-of-bounds-write-via-device-groups-udp

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-119756? +

CVE-2026-119756 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0049, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-119756? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-58774

AMI APTIOV contains vulnerabilities in BIOS where users may cause “Buffer Access with Incorrect Length Value” by local access. Successful …

CVE-2026-12087 9.1

Socket versions before 2.041 for Perl have an out-of-bounds heap read. In Socket.xs, pack_ip_mreq_source() checks the length of its source …

CVE-2025-20315 8.6

A vulnerability in the Network-Based Application Recognition (NBAR) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker …

CVE-2026-47711 8.6

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.4, 1.5.1, and …

CVE-2024-37305 8.2

oqs-provider is a provider for the OpenSSL 3 cryptography library that adds support for post-quantum cryptography in TLS, X.509, and …

CVE-2025-23318 8.1

NVIDIA Triton Inference Server for Windows and Linux contains a vulnerability in the Python backend, where an attacker could cause …