CVE-2026-38426Public exploitNetwork attack vector

Unauthenticated code execution via unbounded MJPEG boundary copy

Published May 27, 2026 · Updated May 27, 2026

Classic buffer overflow in Tasmota 15.3.0.3 and earlier allows remote attackers to execute arbitrary code via a crafted MJPEG response. In fetch_jpg(), an unbounded strcpy() copies the boundary parameter from an HTTP Content-Type header into the fixed 40-byte jpg_task.boundary buffer, corrupting adjacent state. Exploitation requires the device to fetch an MJPEG stream from an attacker-controlled server; successful corruption can crash the device or redirect execution through adjacent client-object pointers.

CVSS severity7.3
High
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Classic buffer overflow in Tasmota 15.3.0.3 and earlier allows remote attackers to execute arbitrary code via a crafted MJPEG response. In fetch_jpg(), an unbounded strcpy() copies the boundary parameter from an HTTP Content-Type header into the fixed 40-byte jpg_task.boundary buffer, corrupting adjacent state. Exploitation requires the device to fetch an MJPEG stream from an attacker-controlled server; successful corruption can crash the device or redirect execution through adjacent client-object pointers.

The record

CVE
CVE-2026-38426
Published
May 27, 2026
Updated
May 27, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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