PatchSiren cyber security CVE debrief
CVE-2026-38422 arendst CVE debrief
A buffer overflow vulnerability exists in the Tasmota open-source firmware, specifically within the Scripter driver component. The flaw resides in the fetch_jpg() function located in xdrv_10_scripter.ino, affecting version 15.3.0.3 and earlier. Successful exploitation by a remote attacker could result in arbitrary code execution on affected devices. The vulnerability was disclosed on May 27, 2026, with the CVE record subsequently modified later the same day. Tasmota is widely deployed in IoT and home automation devices, making this vulnerability potentially significant for environments utilizing the Scripter functionality with image fetching capabilities.
- Vendor
- arendst
- Product
- Tasmota
- CVSS
- HIGH 7.3
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-27
- Original CVE updated
- 2026-05-28
- Advisory published
- 2026-05-27
- Advisory updated
- 2026-05-28
Who should care
Organizations and individuals deploying Tasmota-based IoT devices, particularly those utilizing the Scripter driver for automation scripts involving image processing. Home automation enthusiasts, managed service providers for smart building infrastructure, and industrial IoT deployments using Tasmota firmware should prioritize assessment and patching.
Technical summary
The vulnerability is a buffer overflow in the fetch_jpg() function within the Tasmota Scripter driver (xdrv_10_scripter.ino). This function appears to handle JPEG image fetching operations, suggesting the attack vector involves processing malformed image data or oversized responses. The remote attack vector indicates that network-accessible Tasmota devices with Scripter-enabled image fetching functionality are at risk. Arbitrary code execution capability implies complete device compromise is possible.
Defensive priority
high
Recommended defensive actions
- Upgrade Tasmota firmware to a version newer than 15.3.0.3 when available
- Review and restrict network access to Tasmota devices utilizing Scripter functionality, particularly those with fetch_jpg() capabilities
- Disable the Scripter driver (xdrv_10_scripter.ino) if not required for device operation
- Monitor vendor security advisories and the Tasmota GitHub repository for official patches
- Implement network segmentation to isolate IoT devices from critical infrastructure
- Review device logs for anomalous activity related to image fetching operations
Evidence notes
CVE description identifies specific vulnerable function (fetch_jpg()) and file path (tasmota/tasmota_xdrv_driver/xdrv_10_scripter.ino). A third-party GitHub repository has been created for this CVE identifier, suggesting potential proof-of-concept or technical analysis availability. NVD status is currently 'Deferred', indicating the entry may be under review or awaiting additional analysis.
Official resources
2026-05-27