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Fencer Intel
high 7.5

CVE-2026-55391 json

datamodel-code-generator vulnerable to SSRF protection bypass via DNS rebinding

published 4mo ago modified yesterday also EUVD-2026-50076 , GHSA-vx7x-vcc2-c44g , PYSEC-2026-3565

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

datamodel-code-generator generates Pydantic v2 models, dataclasses, TypedDict, and msgspec.Struct from OpenAPI, JSON Schema, GraphQL, Avro, Protobuf, and raw JSON, YAML, or CSV. Prior to 0.63.0, datamodel-code-generator validates a URL host once in src/datamodel_code_generator/http.py through get_body, _validate_url_for_fetch, and _get_ips_from_host, but then lets httpx resolve the host again for the connection, allowing DNS rebinding to bypass allow_private_network=False and reach internal services. This issue is fixed in version 0.63.0.

Patch / fix

  • pypi datamodel-code-generator 0.63.0
  • koxudaxi datamodel-code-generator 0.63.0
  • python-datamodel-code-generator openSUSE Tumbleweed 0.72.3-1.1

opensuse advisories openSUSE-SU-2026:11538-1

Is CVE-2026-55391 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • gist.github.com https://gist.github.com/thegr1ffyn/c1d54dd6ff2a4c0d7d0dabe00c4985f4 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/koxudaxi/datamodel-code-generator/security/advisories/GHSA-vx7x-vcc2-c44g referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi datamodel-code-generator
<0.63.0
0.63.0

Affected products

  • koxudaxi datamodel-code-generator

Classification

Weakness
  • CWE-350 Reliance on Reverse DNS Resolution for a Security-Critical Action
  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
  • CWE-918 Server-Side Request Forgery

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of datamodel-code-generator/datamodel-code-generator published their own advisory on GitHub. Reviewed sources take precedence over it.