Quick answers
- Is CVE-2026-38422 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-38422 being exploited in the wild.
- How severe is CVE-2026-38422?
- Informational severity, with a CVSS score of 9.8, published 27 May 2026.
- Which products and versions are affected?
- Tasmota <= 15.3.0.3.
- Is there a fix for CVE-2026-38422?
- A patch was published on 2026-05-01: Patch released in Tasmota v15.3.0.4+ Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-38422 attacked?
- It is attacked over the network, in device firmware.
- Am I affected by CVE-2026-38422?
- Check whether you run Tasmota at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists within the fetch_jpg() function in the scripter driver (xdrv_10_scripter.ino). It consists of two compounding memory corruption issues: a strcpy() overflow into a fixed 40-byte boundary buffer (Phase 1) and a uint16_t integer wraparound on the Content-Length header (Phase 2). By hosting a malicious MJPEG server or performing a Man-in-the-Middle (MitM) attack, an attacker can send a crafted HTTP response that corrupts heap memory, including WiFiClient and HTTPClient vtable pointers. This leads to arbitrary code execution or a persistent denial-of-service (crash loop) on ESP32-based devices. The vulnerability is addressed in Tasmota version 15.3.0.4 and later.
Affected products
- arendst Tasmota <= 15.3.0.3
Timeline
- 2026-03-29: disclosed: Vulnerabilities discovered and reported to MITRE
- 2026-05-27: advisory: CVE published by NVD/MITRE
- 2026-05-01: patched: Patch released in Tasmota v15.3.0.4+