Submit #836746: Arendst Tasmota 15.3.0.3 Memory Corruptioninfo

TitleArendst Tasmota 15.3.0.3 Memory Corruption
DescriptionA buffer overflow vulnerability exists in Arendst Tasmota firmware version x.x.x.x and prior in tasmota/tasmota_xdrv_driver/ xdrv_10_scripter.ino within the fetch_jpg() function (case 0). The vulnerable code copies a server-controlled MJPEG boundary string into a fixed-size 40-byte buffer (boundary[40]) using strcpy() without any length validation: char boundary[40]; strcpy(glob_script_mem.jpg_task.boundary, cp + 1); An attacker controlling the MJPEG HTTP server sends a Content-Type header with boundary string longer than 39 characters. This corrupts adjacent heap memory including WiFiClient and HTTPClient vtable pointers at offsets +0x2E and +0x7E, leading to remote code execution when virtual methods are subsequently called on ESP32-based devices. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (9.8 Critical) CVE-2026-38427 PoC: https://github.com/sermikr0/CVE-2026-38427
Source⚠️ https://github.com/sermikr0/CVE-2026-38427
User sermikro (UID 98509)
Submission05/25/2026 12:27 (16 days ago)
Moderation06/07/2026 21:58 (13 days later)
StatusDuplicate
VulDB entry366175 [arendst Tasmota up to 15.3.0.3 fetch_jpg uint16_t heap-based overflow]
Points0

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