CVE-2026-27664Network attack vector

Unauthenticated service crash via crafted XML parsing

Published Mar 26, 2026 · Updated Mar 26, 2026

Out-of-bounds write in Siemens CPCI85 before 26.10 and SICORE before 26.10.0 allows remote attackers to crash services via crafted XML requests. The XML parser writes beyond an intended buffer while processing specially crafted XML input; Siemens has not disclosed a narrower function or field. No authentication or user interaction is required, and the documented consequence is a service crash without confidentiality or integrity impact.

CVSS severity7.5
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Siemens CPCI85 before 26.10 and SICORE before 26.10.0 allows remote attackers to crash services via crafted XML requests. The XML parser writes beyond an intended buffer while processing specially crafted XML input; Siemens has not disclosed a narrower function or field. No authentication or user interaction is required, and the documented consequence is a service crash without confidentiality or integrity impact.

The record

CVE
CVE-2026-27664
Published
Mar 26, 2026
Updated
Mar 26, 2026
Vendor
Siemens
Product
SICORE Base system
Classifications
CWE-787, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 26, 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?

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

  1. Affected versionversion=0 <V26.10.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SICORE Base systemversion=0 <V26.10.0
Siemens · CPCI85 Central Processing/Communicationversion=0 <V26.10

Published CVSS scores

7.5Siemens AGCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7Siemens AGCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499.004Application or System Exploitation

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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