CVE-2026-73233 is a context-blinding vulnerability in FreeCAD's FEM constraint dialog. The issue lies in a helper function that wraps user input for Python execution via doCommand(). The developer implemented quote escaping—correctly identifying that untrusted input in a command-execution path needed boundary enforcement. What was missed: backslashes. The C++ code escapes quotes, but the sanitized string feeds into Python's string parser. In Python, backslashes before quotes and other characters create escape sequences that break out of the intended string literal, allowing arbitrary Python code injection after the C++-level escaping has already been applied. The attacker doesn't bypass the quoting; they escape through it using the backslash character that C++ treats as literal but Python interprets as an escape introducer. This is the fundamental failure: the developer modeled one parsing layer (C++) and applied the canonical SQL-injection defense (quote escaping) without accounting for the downstream interpreter (Python) that consumes the output. The domain context—FEM engineers writing mathematical formulas—likely contributed to implicit trust in the input, since backslashes are syntactically meaningful in formula notation. The fix adds backslash handling to the same helper function. For defenders: audit every call site that passes user input to doCommand() or equivalent dynamic execution APIs. The existence of a centralized escaping helper creates a blast radius risk—one developer's partial sanitization may be implicitly trusted across many call sites. Treat any GUI dialog accept() handler that routes to command execution as a mandatory security review trigger. The specific pattern to hunt: quote-escaping without backslash-handling in any code path that produces strings for interpretation by another language runtime.
CVE-2026-73233
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedFreeCAD is a free and open-source multiplatform 3D parametric modeler. Prior to 1.1.2, the FEM Displacement Constraint task dialog in src/Mod/Fem/Gui/TaskFemConstraintDisplacement.cpp passes the xDisplacementFormula, yDisplacementFormula, and zDisplacementFormula fields of a Fem::ConstraintDisplacement object through TaskDlgFemConstraintDisplacement::accept() into Gui::Command::doCommand. The escaping helper neutralizes quotation marks but not backslashes, allowing crafted formula text to terminate the generated Python string and execute arbitrary Python code with the FreeCAD process's privileges when a victim accepts the dialog. This issue is fixed in version 1.1.2.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisThe application evaluates attacker-influenced input as code, handing them a way to run logic inside the process. Depending on the runtime this can escalate directly to remote code execution. Remediation means removing dynamic evaluation of untrusted input and replacing it with safe, data-driven alternatives.
General guidance for the code injection class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- None
- Authentication
- X
- User interaction
- P
- Scope
- X
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.1.2
- Download FreeCAD version 1.1.2 from the official FreeCAD GitHub releases page (github.com/FreeCAD/FreeCAD/releases) or your distribution's package manager
- Verify the downloaded installer/package matches version 1.1.2 before installing
- Install the new version, replacing any existing FreeCAD installation
- After upgrading, verify the installation by checking Help > About FreeCAD shows version 1.1.2
Generated from the published advisory — verify against the referenced sources before acting.
There is no version to upgrade to and no patch to apply. Every affected install stays exposed until the vendor ships a fix — or somebody else builds one.
Free. We build fixes in the order the community asks for them — and we’ll tell you the moment this one lands.
We develop and verify an original fix where the vendor hasn’t, from $8,000. Deployed to your staging first — never straight to production.
Scope it with usSee what else the community needs solved on the solutions-needed board.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-73233 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesCVE-2026-73233 is a context-blinding vulnerability in FreeCAD's FEM constraint dialog. The issue lies in a helper function that wraps user input for Python execution via doCommand(). The developer implemented quote escaping—correctly identifying that untrusted input in a command-execution path needed boundary enforcement. What was missed: backslashes. The C++ code escapes quotes, but the sanitized string feeds into Python's string parser. In Python, backslashes before quotes and other characters create escape sequences that break out of the intended string literal, allowing arbitrary Python code injection after the C++-level escaping has already been applied. The attacker doesn't bypass the quoting; they escape through it using the backslash character that C++ treats as literal but Python interprets as an escape introducer. This is the fundamental failure: the developer modeled one parsing layer (C++) and applied the canonical SQL-injection defense (quote escaping) without accounting for the downstream interpreter (Python) that consumes the output. The domain context—FEM engineers writing mathematical formulas—likely contributed to implicit trust in the input, since backslashes are syntactically meaningful in formula notation. The fix adds backslash handling to the same helper function. For defenders: audit every call site that passes user input to doCommand() or equivalent dynamic execution APIs. The existence of a centralized escaping helper creates a blast radius risk—one developer's partial sanitization may be implicitly trusted across many call sites. Treat any GUI dialog accept() handler that routes to command execution as a mandatory security review trigger. The specific pattern to hunt: quote-escaping without backslash-handling in any code path that produces strings for interpretation by another language runtime.
Practitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-73233 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data