Security readout for executives and security teams
Plain-English summary
CVE-2021-27399 affects Siemens Simcenter Femap. A malicious FEMAP file could trigger memory corruption in femap.exe and allow code execution as the user who opens it. The strongest business concern is compromise through engineering file workflows, not remote internet exposure.
Executive priority
Prioritize remediation where Femap is used for external collaboration or supplier file exchange. The issue can lead to user-context code execution, but available sources do not show active exploitation.
Technical view
The issue is CWE-787: an out-of-bounds write when femap.exe parses user-supplied FEMAP files. Siemens lists Simcenter Femap 2020.2 before V2020.2.MP3 and 2021.1 before V2021.1.MP3 as affected. ZDI tracks it as ZDI-CAN-12820 and notes it is distinct from CVE-2021-27387.
Likely exposure
Organizations using affected Simcenter Femap versions are exposed when users open FEMAP files from external, shared, or untrusted sources. Exposure is likely workstation-centered and tied to engineering collaboration workflows.
Exploitation context
The provided sources do not state active exploitation, and the CVE is not marked KEV. The described attack requires a crafted FEMAP file and code execution occurs in the current femap.exe process context.
Researcher notes
This is a file-parsing memory corruption issue, not a network service exposure. Focus validation on affected versions, file handling paths, and Siemens advisory alignment. Do not treat CVE-2021-27387 details as interchangeable.
Mitigation direction
- Upgrade affected Femap 2020.2 installations to V2020.2.MP3 or later.
- Upgrade affected Femap 2021.1 installations to V2021.1.MP3 or later.
- Review Siemens SSA-133038 for vendor-specific remediation guidance.
- Limit opening FEMAP files from untrusted or unauthenticated sources.
- Apply endpoint controls around engineering workstations handling external files.
Validation and detection
- Inventory hosts running Simcenter Femap 2020.2 or 2021.1.
- Verify installed maintenance pack level against Siemens affected-version ranges.
- Confirm femap.exe version is not below the fixed MP3 release.
- Review engineering file intake paths for external FEMAP files.
- Check whether endpoint controls cover Femap file-opening workflows.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-787: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-27399 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://cert-portal.siemens.com/productcert/pdf/ssa-133038.pdfCVE reference · x_refsource_MISC
- https://www.zerodayinitiative.com/advisories/ZDI-21-781/CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.