CVE-2026-38427: Heap Overflow (CVSS 7.3)

Description

An issue in fetch_jpg() in xdrv_10_scripter.ino in Tasmota through 15.3.0.3 allows a remote attacker to cause heap buffer overflow. The Content-Length from a JPEG stream is stored in a uint16_t variable; values above 65535 wrap around, causing allocation of a smaller buffer than the data actually read.

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CVSS v3.1 Score

7.3

HIGH

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

EPSS — Exploit Prediction

0.0044

Probability of exploitation

0.35%

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-122 CWE-122

References

Other References

https://github.com/arendst/Tasmota/blob/c207cc2/tasmota/tasmota_xdrv_driver/xdrv_10_scripter.ino https://github.com/sermikr0/CVE-2026-38427 https://github.com/sermikr0/CVE-2026-38427

Frequently Asked Questions

What is CVE-2026-38427? +

An issue in fetch_jpg() in xdrv_10_scripter.ino in Tasmota through 15.3.0.3 allows a remote attacker to cause heap buffer overflow. The Content-Length from a JPEG stream is stored in a uint16_t variable; values above 65535 wrap around, causing allocation of a smaller buffer than the data actually read. It has a CVSS v3.1 base score of 7.3 (HIGH).

How severe is CVE-2026-38427? +

CVE-2026-38427 has a CVSS v3.1 score of 7.3 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0044, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-38427? +

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.

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CVE-2026-38427