ICSA-21-350-17: Siemens JT Utilities and JT Open Toolkit

CISA's summary

Summary: JT Open Toolkit (JTTK) before V11.1.1.0 contains multiple vulnerabilities that could be triggered when it reads a maliciously crafted JT file. These vulnerabilities also affects JT Utilities before V13.1.1.0. If a user is tricked to open a malicious JT file with any of the affected products, this could lead the application to crash or potentially lead to arbitrary code execution. Siemens recommends to update to the latest versions and to limit opening of untrusted files from unknown sources in the affected products.

Products, as the advisory lists them

DeSpy has not checked any unit, hardware revision or firmware.

Vulnerabilities in this advisory

• CVE-2021-44430 — CVE-2021-44430 · CWE-787

  JTTK library in affected products is vulnerable to an out of bounds write past the end of an allocated structure while parsing specially crafted JT files. This could allow an attacker to execute code in the context of the current process. (ZDI-CAN-14829)

• CVE-2021-44431 — CVE-2021-44431 · CWE-125

  JTTK library in affected products is vulnerable to an out of bounds read past the end of an allocated buffer when parsing specially crafted JT files. An attacker could leverage this vulnerability to leak information in the context of the current process. (ZDI-CAN-14841)

• CVE-2021-44432 — CVE-2021-44432 · CWE-121

  JTTK library in affected products is vulnerable to stack based buffer overflow while parsing specially crafted JT files. An attacker could leverage this vulnerability to execute code in the context of the current process. (ZDI-CAN-14845)

• CVE-2021-44433 — CVE-2021-44433 · CWE-416

  JTTK library in affected products contains a use after free vulnerability that could be triggered while parsing specially crafted JT files. An attacker could leverage this vulnerability to execute code in the context of the current process. (ZDI-CAN-14900)

• CVE-2021-44434 — CVE-2021-44434 · CWE-787

  JTTK library in affected products is vulnerable to an out of bounds write past the end of an allocated structure while parsing specially crafted JT files. This could allow an attacker to execute code in the context of the current process. (ZDI-CAN-14902, ZDI-CAN-14866)

• CVE-2021-44435 — CVE-2021-44435 · CWE-121

  JTTK library in affected products is vulnerable to stack based buffer overflow while parsing specially crafted JT files. An attacker could leverage this vulnerability to execute code in the context of the current process. (ZDI-CAN-14903)

• CVE-2021-44436 — CVE-2021-44436 · CWE-125

  JTTK library in affected products is vulnerable to an out of bounds read past the end of an allocated buffer when parsing specially crafted JT files. An attacker could leverage this vulnerability to leak information in the context of the current process. (ZDI-CAN-14905)

• CVE-2021-44437 — CVE-2021-44437 · CWE-787

  JTTK library in affected products is vulnerable to an out of bounds write past the end of an allocated structure while parsing specially crafted JT files. This could allow an attacker to execute code in the context of the current process. (ZDI-CAN-14906)

• CVE-2021-44438 — CVE-2021-44438 · CWE-787

  JTTK library in affected products is vulnerable to an out of bounds write past the end of an allocated structure while parsing specially crafted JT files. This could allow an attacker to execute code in the context of the current process. (ZDI-CAN-14907)

• CVE-2021-44439 — CVE-2021-44439 · CWE-125

  JTTK library in affected products is vulnerable to an out of bounds read past the end of an allocated buffer when parsing specially crafted JT files. An attacker could leverage this vulnerability to leak information in the context of the current process. (ZDI-CAN-14908)

• CVE-2021-44440 — CVE-2021-44440 · CWE-119

  JTTK library in affected products is vulnerable to memory corruption condition while parsing specially crafted JT files. An attacker could leverage this vulnerability to execute code in the context of the current process. (ZDI-CAN-14912)

• CVE-2021-44441 — CVE-2021-44441 · CWE-787

  JTTK library in affected products contains an out of bounds write past the end of an allocated structure while parsing specially crafted JT files. This could allow an attacker to execute code in the context of the current process. (ZDI-CAN-14913)

• CVE-2021-44442 — CVE-2021-44442 · CWE-122

  JTTK library in affected products contains an out of bounds write past the fixed-length heap-based buffer while parsing specially crafted JT files. This could allow an attacker to execute code in the context of the current process. (ZDI-CAN-14995)

• CVE-2021-44443 — CVE-2021-44443 · CWE-787

  JTTK library in affected products contains an out of bounds write past the end of an allocated structure while parsing specially crafted JT files. This could allow an attacker to execute code in the context of the current process. (ZDI-CAN-15039)

• CVE-2021-44444 — CVE-2021-44444 · CWE-125

  JTTK library in affected products is vulnerable to an out of bounds read past the end of an allocated buffer when parsing specially crafted JT files. An attacker could leverage this vulnerability to leak information in the context of the current process. (ZDI-CAN-15052)

• CVE-2021-44445 — CVE-2021-44445 · CWE-122

  JTTK library in affected products contains an out of bounds write past the fixed-length heap-based buffer while parsing specially crafted JT files. This could allow an attacker to execute code in the context of the current process. (ZDI-CAN-15054)

Acknowledgments, as the advisory lists them

• Siemens ProductCERT: reporting this vulnerability to CISA.
• Bentley Systems Incorporated: coordinated disclosure

The advisory's legal notice

Siemens Security Advisories are subject to the terms and conditions contained in Siemens' underlying license terms or other applicable agreements previously agreed to with Siemens (hereinafter "License Terms"). To the extent applicable to information, software or documentation made available in or through a Siemens Security Advisory, the Terms of Use of Siemens' Global Website (https://www.siemens.com/terms_of_use, hereinafter "Terms of Use"), in particular Sections 8-10 of the Terms of Use, shall apply additionally. In case of conflicts, the License Terms shall prevail over the Terms of Use.

Sources

• The advisory at cisa.gov
• The CSAF document (JSON)

DeSpy's copy of this version is dated 2026-09-28.