CVE-2026-27664
Published: 26 March 2026
Summary
CVE-2026-27664 is a high-severity Out-of-bounds Write (CWE-787) vulnerability. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 27.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-27664 is an out-of-bounds write vulnerability (CWE-787) present in the CPCI85 Central Processing/Communication component across all versions prior to V26.10 and in the SICORE Base system across all versions prior to V26.10.0. The flaw occurs during the parsing of specially crafted XML inputs, which can lead to memory corruption in the affected applications.
An unauthenticated attacker can exploit this vulnerability over the network with low attack complexity and no user interaction or privileges required, as reflected in its CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). By transmitting a malicious XML request to the vulnerable service, the attacker triggers the out-of-bounds write, causing the service to crash and resulting in a denial-of-service condition with high availability impact.
Mitigation guidance is available in the Siemens product CERT advisory (SSA-246443) at https://cert-portal.siemens.com/productcert/html/ssa-246443.html and the Full Disclosure mailing list posting at http://seclists.org/fulldisclosure/2026/Apr/7, which detail patching to version V26.10 or later and other recommended protective measures.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-16181
Vulnerability details
A vulnerability has been identified in CPCI85 Central Processing/Communication (All versions < V26.10), SICORE Base system (All versions < V26.10.0). The affected application contains an out-of-bounds write vulnerability while parsing specially crafted XML inputs. This could allow an unauthenticated attacker…
more
to exploit this issue by sending a malicious XML request, which may cause the service to crash, resulting in a denial-of-service condition.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Unauthenticated network exploitation of public-facing XML parser (T1190) directly enables application/system crash via memory corruption (T1499.004).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly remediates the out-of-bounds write vulnerability by applying vendor patches to affected CPCI85 and SICORE versions prior to V26.10.
Validates specially crafted XML inputs to prevent malformed data from triggering the out-of-bounds write during parsing.
Implements memory safeguards such as address space randomization and non-executable regions to mitigate out-of-bounds write memory corruption leading to service crashes.