What’s Vulnerable › Vulnerabilities
CVE-2021-29510: Use of "infinity" as an input to datetime and date fields causes infinite loop in pydantic
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.0% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2021-05-13 · updated 2026-06-17
- Weakness: CWE-835
Description
Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either `'infinity'`, `'inf'` or `float('inf')` (or their negatives) to `datetime` or `date` fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.
Affected products
- Fedoraproject Fedora: 33, 34
- Pydantic: before 1.6.2; from 1.7 before 1.7.4; from 1.8 before 1.8.2 — fixed in 1.6.2, 1.7.4, 1.8.2
- Pypi Pydantic: before 1.6.2; from 1.7 before 1.7.4; from 1.8 before 1.8.2; 0.0.1, 0.0.2, 0.0.3, 0.0.4, 0.0.5, 0.0.6 (+146) — fixed in 1.6.2, 1.7.4, 1.8.2
How to fix
Upgrade to a fixed version: Pydantic 1.6.2, 1.7.4, 1.8.2; Pypi Pydantic 1.6.2, 1.7.4, 1.8.2. Check the vendor advisory for mitigations.
References
- https://github.com/samuelcolvin/pydantic/commit/7e83fdd2563ffac081db7ecdf1affa65ef38c468
- https://github.com/samuelcolvin/pydantic/security/advisories/GHSA-5jqp-qgf6-3pvh
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S2HT266L6Q7H6ICP7DFGXOGBJHNNKMKB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UEFWM7DYKD2ZHE7R5YT5EQWJPV4ZKYRB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UMKAJX4O6IGBBCE32CO2G7PZQCCQSBLV/
- https://github.com/samuelcolvin/pydantic/commit/7e83fdd2563ffac081db7ecdf1affa65ef38c468
- https://github.com/samuelcolvin/pydantic/security/advisories/GHSA-5jqp-qgf6-3pvh
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S2HT266L6Q7H6ICP7DFGXOGBJHNNKMKB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UEFWM7DYKD2ZHE7R5YT5EQWJPV4ZKYRB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UMKAJX4O6IGBBCE32CO2G7PZQCCQSBLV/
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