CVE
datamodel-code-generator < 0.84.0 Code Injection via x-python-type Annotation
Affects datamodel-code-generator before 0.84.0 when generated models are evaluated by Pydantic v2 during model_rebuild(). Fixed in 0.84.0.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 0.84.0
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. datamodel-code-generator versions before 0.84.0 Attacker supplies a malicious JSON Schema with a crafted x-python-type annotation Generated models are evaluated by Pydantic v2 during model_rebuild()
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 21/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The datamodel-code-generator tool, before version 0.84.0 (version omitted per rules), has a code injection flaw that lets an attacker run arbitrary code by supplying a malicious JSON Schema with a crafted x-python-type annotation. The attack can be reached remotely over the network without logging in, but it requires a user to take an action, and it affects developer workstations, CI/CD pipelines, and applications that import the generated models.
Read the original description
datamodel-code-generator before 0.84.0 contains a code injection vulnerability that allows attackers to achieve arbitrary code execution by supplying a malicious JSON Schema with a crafted x-python-type annotation containing a string ast.Constant node in a subscript slice position, which bypasses validation in parse_python_type_annotation and _python_type_expr_from_ast. Attackers can embed malicious Python expressions such as __import__ calls within quoted string literals in the generated source code, which Pydantic v2 evaluates as a ForwardRef via eval() during model_rebuild(), resulting in arbitrary code execution on developer workstations, CI/CD pipelines, or applications that generate and import the produced models at runtime.
Who should check
Teams running datamodel-code-generator before 0.84.0, including developer workstations, CI/CD pipelines, and apps that generate and import models at runtime
Read the source excerpt
“datamodel-code-generator before 0.84.0 contains a code injection vulnerability”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.6/10CVSS 8.6
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
What to do
Check whether your setup matches what the bug needs.
datamodel-code-generator versions before 0.84.0 Attacker supplies a malicious JSON Schema with a crafted x-python-type annotation Generated models are evaluated by Pydantic v2 during model_rebuild()Upgrade to a fixed version: 0.84.0.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-127208 (datamodel-code-generator < 0.84.0 Code Injection via x-python-type Annotation), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-127208 (entry last updated 2026-11-12):
Affected:
- datamodel-code-generator datamodel-code-generator: fixed in 0.84.0
Fixed versions: 0.84.0.
Conditions (all must be true for the bug to be hit):
- datamodel-code-generator versions before 0.84.0 (source: https://www.vulncheck.com/advisories/datamodel-code-generator-code-injection-via-x-python-type-annotation)
- Attacker supplies a malicious JSON Schema with a crafted x-python-type annotation (source: https://www.vulncheck.com/advisories/datamodel-code-generator-code-injection-via-x-python-type-annotation)
- Generated models are evaluated by Pydantic v2 during model_rebuild() (source: https://www.vulncheck.com/advisories/datamodel-code-generator-code-injection-via-x-python-type-annotation)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, a user action.
CISA KEV: CVE-2026-127208 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-127208 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/datamodel-code-generator/datamodel-code-generator/commit/ebfc11d0644d37a71374b28aac06d98748e584ec
- https://github.com/datamodel-code-generator/datamodel-code-generator/releases/tag/0.84.0
- https://www.vulncheck.com/advisories/datamodel-code-generator-code-injection-via-x-python-type-annotation
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-127208
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-127208"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- datamodel-code-generator datamodel-code-generator
fixed in 0.84.0
Evidence 5
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-127208
Is CVE-2026-127208 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A malicious JSON Schema with a crafted x-python-type annotation can lead to arbitrary code execution. Pydantic v2 evaluates the annotation as a ForwardRef via eval() during model_rebuild().Source: vulncheck.com
Which versions are affected by CVE-2026-127208?
datamodel-code-generator: before 0.84.0.Source: cve.now feed data
Am I affected, and how do I check?
The issue affects datamodel-code-generator versions before 0.84.0. Generated models that are evaluated by Pydantic v2 during model_rebuild() are the setup in which it applies. The installed version can be checked with pip show datamodel-code-generator.Source: vulncheck.com
How do I fix CVE-2026-127208?
Upgrade datamodel-code-generator to 0.84.0 or later, which is the listed fixed version.Source: vulncheck.com