CVE-2026-78319Network attack vector

Unauthenticated code execution via firmware update race

Published Sep 1, 2026 · Updated Sep 1, 2026

TOCTOU in the firmware update service of SAUTER building controllers allows remote attackers to execute unauthorized code. The vendor identifies a race between checking and using an update resource but does not disclose the resource, operation, or request sequence that opens the race. No authentication or user interaction is required, and successful exploitation grants full control of the controller and its building-automation functions.

CVSS severity9.8
Critical
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

TOCTOU in the firmware update service of SAUTER building controllers allows remote attackers to execute unauthorized code. The vendor identifies a race between checking and using an update resource but does not disclose the resource, operation, or request sequence that opens the race. No authentication or user interaction is required, and successful exploitation grants full control of the controller and its building-automation functions.

The record

CVE
CVE-2026-78319
Published
Sep 1, 2026
Updated
Sep 1, 2026
Vendor
Fr. Sauter AG
Product
SAUTER modu680-AS
Classifications
CWE-367, CAPEC-29, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.0 <4.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fr. Sauter AG · SAUTER modu680-ASversion=1.0.0 <4.0.0
Fr. Sauter AG · SAUTER ecos504version=1.0.0 <7.0.0
Fr. Sauter AG · SAUTER modu612-LCversion=1.0.0 <4.0.0
Fr. Sauter AG · SAUTER ecos505version=1.0.0 <7.0.0
Fr. Sauter AG · SAUTER modu660-ASversion=1.0.0 <4.0.0

Published CVSS scores

9.8CERT@VDECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.3CERT@VDE CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
CAPEC-29Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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