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Fencer Vulns
high 7.5

CVE-2026-55391 json

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

published 2026-07-28 3 mo ago modified 2026-10-23 16 d ago also GHSA-vx7x-vcc2-c44g , PYSEC-2026-3565 , EUVD-2026-50076

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

CISA SSVC

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

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

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
OSV 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

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 Vulns 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.