CVE-2026-25789Network attack vector

Session hijacking via unsanitized firmware filename

Published May 12, 2026 · Updated May 12, 2026

Cross-site scripting in Siemens SIMATIC S7 PLC web servers allows remote attackers to execute JavaScript through a crafted firmware filename. The Firmware Update page renders the selected file's name without proper validation or sanitization, so script runs before any upload occurs. An authenticated user with firmware-update rights must select the crafted file; execution can steal credentials or hijack that user's session.

CVSS severity7.2
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Siemens SIMATIC S7 PLC web servers allows remote attackers to execute JavaScript through a crafted firmware filename. The Firmware Update page renders the selected file's name without proper validation or sanitization, so script runs before any upload occurs. An authenticated user with firmware-update rights must select the crafted file; execution can steal credentials or hijack that user's session.

The record

CVE
CVE-2026-25789
Published
May 12, 2026
Updated
May 12, 2026
Vendor
Siemens
Product
SIMATIC S7-1500 CPU 1518T-4 PN/DP
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 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=0 <V3.1.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Siemens · SIMATIC S7-1500 CPU 1518T-4 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 CPU 1515T-2 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 ET 200pro: CPU 1516PRO F-2 PNversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1507S F V2version=0 <*
Siemens · SIPLUS ET 200SP CPU 1510SP-1 PN RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1507S V3version=0 <*
Siemens · SIMATIC ET 200SP CPU 1514SP F-2 PNversion=0 <*
Siemens · SIPLUS ET 200SP CPU 1510SP F-1 PN RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1508S V4version=0 <*
Siemens · SIMATIC S7-1500 CPU 1517F-3 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 ET 200pro: CPU 1513PRO F-2 PNversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1517TF-3 PN/DPversion=0 <V3.1.6
Siemens · SIPLUS S7-1500 CPU 1516F-3 PN/DP RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1516TF-3 PNversion=0 <*
Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=0 <V3.1.6
Siemens · SIMATIC ET 200SP Open Controller CPU 1515SP PC3version=0 <*
Siemens · SIMATIC S7-1500 CPU 1516-3 PN/DPversion=0 <*; version=0 <V2.9.9
Siemens · SIPLUS S7-1500 CPU 1516-3 PN/DP RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1518TF-4 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 CPU 1517TF-3 PNversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1517T-3 PNversion=0 <*
Siemens · SIPLUS ET 200SP CPU 1510SP F-1 PNversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1508S TFversion=0 <*
Siemens · SIMATIC ET 200SP Open Controller CPU 1515SP PC2version=0 <*
Siemens · SIMATIC S7-1500 CPU 1517F-3 PNversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1511F-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1508S Tversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP ODKversion=0 <*
Siemens · SIPLUS S7-1500 CPU 1518F-4 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 CPU 1511TF-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC ET 200SP CPU 1514SPT-2 PNversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1518TF-3 PNversion=0 <*
Siemens · SIPLUS ET 200SP CPU 1512SP F-1 PN RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1513-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC Drive Controller CPU 1507D TFversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 CPU 1516F-3 PN/DPversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 ET 200pro: CPU 1513PRO-2 PNversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU S7-1518F-4 PN/DP ODKversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1511T-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1507Sversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1518-3 PNversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 Software Controller Linuxversion=0 <*
Siemens · SIPLUS S7-1500 CPU 1511-1 PN T1 RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1507S Fversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1511-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIPLUS S7-1500 CPU 1511F-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIPLUS ET 200SP CPU 1512SP-1 PNversion=0 <V2.9.9
Siemens · SIMATIC S7-PLCSIM Advancedversion=0 <*
Siemens · SIMATIC S7-1500 Software Controller CPU 1508S Fversion=0 <*
Siemens · SIPLUS S7-1500 CPU 1511-1 PN TX RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1508S F V3version=0 <*
Siemens · SIPLUS S7-1500 CPU 1515F-2 PNversion=0 <V2.9.9
Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC ET 200SP CPU 1510SP F-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1513F-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1516T-3 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC ET 200SP Open Controller CPU 1515SP PCversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1516pro F-2 PNversion=0 <*
Siemens · SIPLUS S7-1500 CPU 1513-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIPLUS S7-1500 CPU 1516F-3 PN/DPversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1517-3 PNversion=0 <*
Siemens · SIPLUS S7-1500 CPU 1513F-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC ET 200SP CPU 1512SP F-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIPLUS S7-1500 CPU 1516-3 PN/DPversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 CPU 1512C-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1516pro-2 PNversion=0 <*
Siemens · SIPLUS S7-1500 CPU 1511-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1513pro F-2 PNversion=0 <*
Siemens · SIMATIC S7-1500 Software Controller CPU 1508Sversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1515F-2 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC ET 200SP CPU 1512SP-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIPLUS ET 200SP CPU 1512SP-1 PN RAILversion=0 <V2.9.9
Siemens · SIMATIC Drive Controller CPU 1504D TFversion=0 <V3.1.6
Siemens · SIPLUS S7-1500 CPU 1516-3 PN/DP TX RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1513pro-2 PNversion=0 <*
Siemens · SIPLUS ET 200SP CPU 1510SP-1 PNversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1517T-3 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 CPU 1511C-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 Software Controller CPU 1507S V2version=0 <*
Siemens · SIMATIC ET 200SP CPU 1514SPT F-2 PNversion=0 <*
Siemens · SIMATIC ET 200SP CPU 1514SP-2 PNversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1515-2 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIPLUS S7-1500 CPU 1515F-2 PN RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 CPU 1516T-3 PNversion=0 <*
Siemens · SIMATIC S7-1500 CPU 1518T-3 PNversion=0 <*
Siemens · SIMATIC S7-1500 Software Controller CPU 1507S F V3version=0 <*
Siemens · SIPLUS S7-1500 CPU 1515F-2 PN T2 RAILversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1515TF-2 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1516TF-3 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC S7-1500 ET 200pro: CPU 1516PRO-2 PNversion=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1517-3 PN/DPversion=0 <V3.1.6
Siemens · SIMATIC ET 200SP CPU 1510SP-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIPLUS ET 200SP CPU 1512SP F-1 PNversion=0 <*; version=0 <V2.9.9
Siemens · SIMATIC S7-1500 CPU 1518F-3 PNversion=0 <*

Published CVSS scores

7.2Siemens ProductCERTCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:A/VC:L/VI:H/VA:H/SC:L/SI:H/SA:H
7.1Siemens ProductCERTCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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